Wiring board and method for manufacturing wiring board

ABSTRACT

A wiring board includes: a substrate having transparency; a plurality of first wirings which are arranged on an upper surface of the substrate and extend in a first direction and each of which has a back surface in contact with the substrate and a front surface facing an opposite side of the back surface; and has a back surface in contact with the substrate and a front surface facing an opposite side of the back surface. The first wiring has a pair of side surfaces which extend in the first direction and are adjacent to the back surface of the first wiring, and each of the pair of side surfaces of the second wiring is recessed inward. The second wiring has a pair of side surfaces which extend in the second direction and are adjacent to the back surface of the second wiring.

TECHNICAL FIELD

Embodiments of the present disclosure relate to a wiring board and amethod for manufacturing a wiring board.

BACKGROUND ART

Recently, mobile terminal devices such as smartphones and tablets havebeen more sophisticated, smaller, thinner, and lighter. Since thesemobile terminal devices use a plurality of communication bands, aplurality of antennas corresponding to the communication bands arerequired. For example, a plurality of antennas, such as telephoneantennas, wireless fidelity (WiFi) antennas, 3 generation (G) antennas,4 generation (G) antennas, long term evolution (LTE) antennas, Bluetooth(registered trademark) antennas, and near field communication (NFC)antennas, are mounted on mobile terminal devices. However, a mountingspace for the antennas has been limited with the miniaturization ofmobile terminal devices, and the degree of freedom in antenna design hasbeen narrowed. Further, the radio wave sensitivity is not alwayssatisfactory because the antennas are built in the limited space.

Thus, a film antenna that can be mounted on a display region of a mobileterminal device has been developed. In this film antenna, an antennapattern is formed of a mesh-like conductor mesh layer having a conductorportion serving as a formation portion of an opaque conductor layer anda large number of opening portions serving as non-formation portions ina transparent antenna in which the antenna pattern is formed on atransparent substrate.

CITATION LIST Patent Literature

Patent Literature 1: JP 2011-66610 A

Patent Literature 2: JP 5636735 B2

Patent Literature 3: JP 5695947 B2

One of objects of an embodiment of the present disclosure is to providea wiring board having a radio wave transmission/reception function withimproved conductivity and transparency, and a method for manufacturingthe same.

Further, one or more mesh antennas are mounted on the transparentsubstrate in the conventional film antenna, but both a region where theantenna pattern is formed and a region where the antenna pattern is notformed are present on the transparent substrate. In this case, theregion where the antenna pattern is formed is likely to be visible dueto the presence of the region where the antenna pattern is not formed.

One of objects of the present embodiment is to provide a wiring boardand a method for manufacturing a wiring board, which can make itdifficult to visually recognize an antenna pattern region.

Further, one or a plurality of mesh antennas are mounted on thetransparent substrate in the conventional film antenna. Whiletransmission and reception are performed using this mesh antenna, acurrent value tends to increase toward an edge of the mesh antenna, andthe current value tends to decrease toward the center. Therefore, acurrent distribution in each of the mesh antennas is not uniform, and itis difficult to sufficiently improve antenna characteristics.

The present embodiment provides the wiring board and the method formanufacturing the wiring board, which can make a current distribution inan antenna pattern region more uniform and improve antennacharacteristics.

SUMMARY OF INVENTION

A wiring board according to one embodiment of the present disclosureincludes: a substrate having transparency; a plurality of first wiringwhich are arranged on an upper surface of the substrate and extend in afirst direction and each of which has a back surface in contact with thesubstrate and a front surface facing an opposite side of the backsurface; and a second wiring which is arranged on the upper surface ofthe substrate, extends in a second direction intersecting with the firstdirection, and has a back surface in contact with the substrate and afront surface facing an opposite side of the back surface, the firstwiring has a pair of side surfaces which extend in the first directionand are adjacent to the back surface of the first wiring, and each ofthe pair of side surfaces of the first wiring is recessed inward, andthe second wiring has a pair of side surfaces which extend in the seconddirection and are adjacent to the back surface of the second wiring, andeach of the pair of side surfaces of the second wiring is recessedinward.

A wiring board according to one embodiment of the present disclosureincludes: a substrate having transparency; a plurality of first wiringwhich are arranged on an upper surface of the substrate and extend in afirst direction and each of which has a back surface in contact with thesubstrate and a front surface facing an opposite side of the backsurface; and a second wiring which is arranged on the upper surface ofthe substrate, extends in a second direction intersecting with the firstdirection, and has a back surface in contact with the substrate and afront surface facing an opposite side of the back surface, the firstwiring has a pair of side surfaces which extend in the first directionand are adjacent to the back surface of the first wiring, the secondwiring has a pair of side surfaces which extend in the second directionand are adjacent to the back surface of the second wiring, and one sidesurface of the first wiring and one side surface of the second wiringare continuously connected by a curved surface.

A wiring board according to one embodiment of the present disclosureincludes: a substrate having transparency; a plurality of first wiringswhich are arranged on an upper surface of the substrate and extend in afirst direction and each of which has a back surface in contact with thesubstrate and a front surface facing an opposite side of the backsurface; and a second wiring which is arranged on the upper surface ofthe substrate, extends in a second direction intersecting with the firstdirection, and has a back surface in contact with the substrate and afront surface facing an opposite side of the back surface, and a linewidth of the back surface of the second wiring is smaller than a linewidth of the back surface of the first wiring.

In the wiring board according to one embodiment of the presentdisclosure, the line width of the back surface of the first wiring maybe larger than a line width of the front surface of the first wiring,and the line width of the back surface of the second wiring may belarger than a line width of the front surface of the second wiring.

In the wiring board according to one embodiment of the presentdisclosure, the second wiring may have a pair of side surfaces whichextend in the second direction and are adjacent to the back surface ofthe second wiring, and an angle between the front surface and each ofthe side surfaces of the second wiring may be smaller than an externalangle of an angle between the back surface and each of the side surfacesof the second wiring.

In the wiring board according to one embodiment of the presentdisclosure, the first wiring may have a pair of side surfaces whichextend in the first direction and are adjacent to the back surface ofthe first wiring, and an angle between the front surface and each of theside surfaces of the first wiring may be smaller than an external angleof an angle between the back surface and each of the side surfaces ofthe first wiring.

In the wiring board according to one embodiment of the presentdisclosure, an intersection between the first wiring and the secondwiring may include a curved surface at at least one of corners formed bythe upper surface of the substrate, a surface adjacent to the backsurface of the first wiring, and a surface adjacent to the back surfaceof the second wiring, the curved surface being continuous among thesurfaces.

The wiring board according to one embodiment of the present disclosuremay have a radio wave transmission/reception function.

A method for manufacturing a wiring board according to one embodiment ofthe present disclosure includes: forming a conductive layer on an uppersurface of a substrate; forming an insulating layer that includes afirst trench extending in a first direction and a second trenchextending in a second direction; forming a first conductor arranged inthe first trench and a second conductor arranged in the second trench;removing the insulating layer; and removing the conductive layer toexpose the upper surface of the substrate and forming a first wiring anda second wiring from the first conductor and the second conductor.

In the method for manufacturing a wiring board according to oneembodiment of the present disclosure, the first wiring may have a pairof side surfaces which extend in the first direction and are adjacent toa back surface of the first wiring, and each of the pair of sidesurfaces of the first wiring may be recessed inward, and the secondwiring may have a pair of side surfaces which extend in the seconddirection and are adjacent to a back surface of the second wiring, andeach of the pair of side surfaces of the second wiring may be recessedinward.

In the method for manufacturing a wiring board according to oneembodiment of the present disclosure, the first wiring may have a pairof side surfaces which extend in the first direction and are adjacent toa back surface of the first wiring, the second wiring may have a pair ofside surfaces which extend in the second direction and are adjacent to aback surface of the second wiring, and one side surface of the firstwiring and one side surface of the second wiring may be continuouslyconnected by a curved surface.

In the method for manufacturing a wiring board according to oneembodiment of the present disclosure, a line width of a back surface ofthe second wiring may be smaller than a line width of a back surface ofthe first wiring.

In the method for manufacturing a wiring board according to oneembodiment of the present disclosure, the insulating layer that includesthe first trench and the second trench may be formed using an imprintingmethod.

In the method for manufacturing a wiring board according to oneembodiment of the present disclosure, a method for forming the firstwiring and the second wiring may include: forming the conductive layerby a sputtering method; forming the first wiring and the second wiringby an electrolytic plating method; and removing the conductive layer bywet etching so as to expose the upper surface of the substrate.

In the method for manufacturing a wiring board according to oneembodiment of the present disclosure, front surfaces of the first wiringand the second wiring may be subjected to a blackening treatment.

According to the embodiments of the present disclosure, it is possibleto provide the wiring board with the improved conductivity andtransparency and the method for manufacturing the same.

A wiring board according to one embodiment of the present disclosure isa wiring board including: a substrate having transparency; a wiringpattern region which is arranged on the substrate and includes aplurality of wirings; and a dummy pattern region which is arrangedaround the wiring pattern region and includes a plurality of dummywirings electrically independent of the wirings, wherein each of thewiring pattern region and the dummy pattern region is formed byrepeating a predetermined unit pattern shape, and a unit pattern shapeof the dummy pattern region is a shape in which a part of a unit patternshape of the wiring pattern region is missing, and an additional patternapart from the dummy wiring is arranged in the dummy pattern region.

In the wiring board according to one embodiment of the presentdisclosure, the dummy wiring may have a first dummy wiring portion and asecond dummy wiring portion, and the first dummy wiring portion and thesecond dummy wiring portion may be arranged apart from each other in aplane direction.

A wiring board according to one embodiment of the present disclosure isa wiring board including: a substrate having transparency; a wiringpattern region which is arranged on the substrate and includes aplurality of wirings; and a dummy pattern region which is arrangedaround the wiring pattern region and includes a plurality of dummywirings electrically independent of the wirings, wherein the dummywiring has a substantially L shape in a plan view.

In the wiring board according to one embodiment of the presentdisclosure, an additional pattern apart from the dummy wiring may bearranged in the dummy pattern region.

A wiring board according to one embodiment of the present disclosure isa wiring board including: a substrate having transparency; a wiringpattern region which is arranged on the substrate and includes aplurality of wirings; and a dummy pattern region which is arrangedaround the wiring pattern region and includes a plurality of dummywirings electrically independent of the wirings, wherein the dummywiring has a first dummy wiring portion and a second dummy wiringportion, and the first dummy wiring portion and the second dummy wiringportion are arranged obliquely with respect to the wiring.

In the wiring board according to one embodiment of the presentdisclosure, an aperture ratio of the dummy pattern region may be higherthan an aperture ratio of the wiring pattern region.

In the wiring board according to one embodiment of the presentdisclosure, the aperture ratio of the dummy pattern region may be in arange of 87% or more and less than 100%.

In the wiring board according to one embodiment of the presentdisclosure, a difference between the aperture ratio of the dummy patternregion and the aperture ratio of the wiring pattern region may be 1% orless.

In the wiring board according to one embodiment of the presentdisclosure, the wiring pattern region may include a plurality ofconnection wirings connecting the plurality of wirings.

The wiring board according to one embodiment of the present disclosuremay have a radio wave transmission/reception function.

According to the embodiments of the present disclosure, it is possibleto make it difficult to visually recognize the wiring pattern region.

A wiring board according to one embodiment of the present disclosure isa wiring board including: a substrate having transparency; and anantenna pattern region which is arranged on the substrate and includes aplurality of antenna wirings having a function as an antenna, wherein anaperture ratio of a widthwise central portion of the antenna patternregion is higher than an aperture ratio of a widthwise edge portion ofthe antenna pattern region.

In the wiring board according to one embodiment of the presentdisclosure, a pitch of the plurality of antenna wirings in the widthwisecentral portion of the antenna pattern region may be wider than a pitchof the plurality of antenna wirings in a widthwise edge portion of theantenna pattern region.

In the wiring board according to one embodiment of the presentdisclosure, a void portion in which the antenna wiring is not providedmay be formed in a widthwise central portion of the antenna patternregion.

In the wiring board according to one embodiment of the presentdisclosure, a dummy pattern region including a plurality of dummywirings electrically independent of the antenna wiring may be formed inthe void portion.

In the wiring board according to one embodiment of the presentdisclosure, the antenna pattern region may have a first pattern regionand a second pattern region separated with the void portiontherebetween, the first pattern region and the second pattern region maybe respectively arranged on both widthwise edge portions of the antennapattern region, and the first pattern region and the second patternregion may be electrically connected to each other by a central patternregion.

In the wiring board according to one embodiment of the presentdisclosure, connection pattern regions each having an inclined portionformed obliquely to a width direction of the antenna pattern region maybe provided between the central pattern region and each of the firstpattern region and the second pattern region.

In the wiring board according to one embodiment of the presentdisclosure, a power feeding unit may be electrically connected to theantenna pattern region, and a length of the power feeding unit in thewidthwise central portion may be longer than a length of the powerfeeding unit in the widthwise edge portion.

A wiring board according to one embodiment of the present disclosure isa wiring board including: a substrate having transparency; an antennapattern region which is arranged on the substrate and includes aplurality of antenna wirings having a function as an antenna; a powerfeeding unit electrically connected to the antenna pattern region,wherein a length of the power feeding unit in a widthwise centralportion is longer than a length of the power feeding unit in a widthwiseedge portion.

A method for manufacturing a wiring board according to one embodiment ofthe present disclosure is a method for manufacturing a wiring boardincluding: a step of preparing a substrate having transparency; and astep of forming an antenna pattern region, which includes a plurality ofantenna wirings each having a function as an antenna, on the substrate,wherein an aperture ratio of a widthwise central portion of the antennapattern region is higher than an aperture ratio of a widthwise edgeportion of the antenna pattern region.

A method for manufacturing a wiring board according to one embodiment ofthe present disclosure is a method for manufacturing a wiring boardincluding: a step of preparing a substrate having transparency; and astep of forming an antenna pattern region including a plurality ofantenna wirings each having a function as an antenna and a power feedingunit electrically connected to the antenna pattern region on thesubstrate, wherein a length of the power feeding unit in a widthwisecentral portion is longer than a length of the power feeding unit in awidthwise edge portion.

According to the embodiment of the present disclosure, the currentdistribution in the antenna pattern region can be made more uniform, andthe antenna characteristic can be improved.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a top view illustrating an example of a wiring board accordingto a first embodiment of the present disclosure.

FIG. 2 is a cross-sectional view illustrating an example of the wiringboard according to the first embodiment of the present disclosure.

FIG. 3 is a cross-sectional view illustrating a first modification ofthe wiring board according to the first embodiment of the presentdisclosure.

FIG. 4 is a cross-sectional view illustrating a second modification ofthe wiring board according to the first embodiment of the presentdisclosure.

FIG. 5 is a cross-sectional view illustrating a third modification ofthe wiring board according to the first embodiment of the presentdisclosure.

FIG. 6 is a cross-sectional view illustrating a fourth modification ofthe wiring board according to the first embodiment of the presentdisclosure.

FIG. 7 is a top view illustrating a fifth modification of the wiringboard according to the first embodiment of the present disclosure.

FIG. 8 is a cross-sectional view illustrating the fifth modification ofthe wiring board according to the first embodiment of the presentdisclosure.

FIG. 9 is a top view illustrating a sixth modification of the wiringboard according to the first embodiment of the present disclosure.

FIG. 10 is a cross-sectional view illustrating the sixth modification ofthe wiring board according to the first embodiment of the presentdisclosure.

FIG. 11 is a cross-sectional view illustrating a method formanufacturing the wiring board according to the first embodiment of thepresent disclosure.

FIG. 12 is a cross-sectional view illustrating the method formanufacturing the wiring board according to the first embodiment of thepresent disclosure.

FIG. 13 is a cross-sectional view illustrating a modification of themethod for manufacturing the wiring board according to the firstembodiment of the present disclosure.

FIG. 14 is a top view illustrating a wireless communication moduleaccording to the first embodiment of the present disclosure.

FIG. 15 is a top view illustrating a modification of the wirelesscommunication module according to the first embodiment of the presentdisclosure.

FIG. 16 is an electron microscope (SEM) image of a cross section of thewiring board according to the first embodiment of the presentdisclosure.

FIG. 17 is an electron microscope (SEM) image of the cross section ofthe wiring board according to the first embodiment of the presentdisclosure.

FIG. 18 is a plan view illustrating a wiring board according to a secondembodiment.

FIG. 19 is an enlarged plan view (enlarged view of Part XIX of FIG. 18)illustrating the wiring board according to the second embodiment.

FIG. 20 is a cross-sectional view (cross-sectional view taken along aline XX-XX of FIG. 19) illustrating the wiring board according to thesecond embodiment.

FIG. 21 is a cross-sectional view (cross-sectional view taken along aline XXI-XXI of FIG. 19) illustrating the wiring board according to thesecond embodiment.

FIG. 22 is a cross-sectional view (cross-sectional view taken along aline XXII-XXII of FIG. 19) illustrating the wiring board according tothe second embodiment.

FIGS. 23(a) to 23(h) are cross-sectional views illustrating a method formanufacturing the wiring board according to the second embodiment.

FIG. 24 is a plan view illustrating an image display device according tothe second embodiment.

FIG. 25 is an enlarged plan view (view corresponding to FIG. 19)illustrating a modification of the wiring board according to the secondembodiment.

FIG. 26 is an enlarged plan view (view corresponding to FIG. 19)illustrating a modification of the wiring board according to the secondembodiment.

FIG. 27 is an enlarged plan view (view corresponding to FIG. 19)illustrating a modification of the wiring board according to the secondembodiment.

FIG. 28 is an enlarged plan view (view corresponding to FIG. 19)illustrating a modification of the wiring board according to the secondembodiment.

FIG. 29 is an enlarged plan view illustrating a modification of thewiring board according to the second embodiment.

FIG. 30 is an enlarged plan view illustrating a modification of thewiring board according to the second embodiment.

FIG. 31 is an enlarged plan view illustrating a modification of thewiring board according to the second embodiment.

FIG. 32 is an enlarged plan view illustrating a modification of thewiring board according to the second embodiment.

FIG. 33 is an enlarged plan view illustrating a modification of thewiring board according to the second embodiment.

FIG. 34 is an enlarged plan view illustrating a modification of thewiring board according to the second embodiment.

FIG. 35 is an enlarged plan view illustrating a modification of thewiring board according to the second embodiment.

FIG. 36 is an enlarged plan view illustrating a modification of thewiring board according to the second embodiment.

FIG. 37 is an enlarged plan view illustrating a modification of thewiring board according to the second embodiment.

FIG. 38 is a plan view illustrating a wiring board according to a thirdembodiment.

FIG. 39 is an enlarged plan view (enlarged view of Part XXXIX of FIG.38) illustrating the wiring board according to the third embodiment.

FIGS. 40(a) and 40(b) are enlarged plan views (enlarged views of PartsXLA and XLB of FIG. 39) illustrating the wiring board according to thethird embodiment.

FIG. 41 is a cross-sectional view (cross-sectional view taken along aline XLI-XLI of FIG. 40) illustrating the wiring board according to thethird embodiment.

FIG. 42 is a cross-sectional view (cross-sectional view taken along aline XLII-XLII of FIG. 40) illustrating the wiring board according tothe third embodiment.

FIGS. 43(a) to 43(h) are cross-sectional views illustrating a method formanufacturing the wiring board according to the third embodiment.

FIG. 44 is a plan view illustrating an image display device according tothe third embodiment.

FIG. 45 is an enlarged plan view (view corresponding to FIG. 39)illustrating a wiring board according to a first modification of thethird embodiment.

FIG. 46 is an enlarged plan view (view corresponding to FIG. 39)illustrating a wiring board according to a second modification of thethird embodiment.

FIG. 47 is an enlarged plan view (view corresponding to FIG. 39)illustrating a wiring board according to a third modification of thethird embodiment.

FIG. 48 is an enlarged plan view (view corresponding to FIG. 39)illustrating a wiring board according to a fourth modification of thethird embodiment.

FIG. 49 is an enlarged plan view (view corresponding to FIG. 39)illustrating a wiring board according to a fifth modification of thethird embodiment.

FIG. 50 is an enlarged plan view (view corresponding to FIG. 39)illustrating a wiring board according to a sixth modification of thethird embodiment.

FIG. 51 is a graph illustrating current values flowing through a uniformmesh-like antenna pattern and a uniform plate-like antenna pattern inthe third embodiment.

DESCRIPTION OF EMBODIMENTS

Each of the following drawings is schematically illustrated. Therefore,a size and a shape of each portion are exaggerated as appropriate inorder to facilitate understanding. Further, it is possible toappropriately change and implement within a scope not departing from atechnical idea. Note that the same portions are denoted by the samereference signs in the following drawings, and a detailed descriptionthereof is sometimes partially omitted. Further, a numerical value suchas a dimension of each member and a material name described in thepresent specification are examples as embodiments, and can beappropriately selected and used without being limited thereto. In thepresent specification, terms specifying a shape and a geometriccondition, such as terms such as parallel, orthogonal, and vertical,include not only one that is strictly meant but also substantially thesame state.

First Embodiment

Hereinafter, a wiring board and a method for manufacturing the sameaccording to a first embodiment will be described with reference to thedrawings. However, the wiring board and the method for manufacturing thesame according to the present embodiment can be carried out in manydifferent modes, and is not construed as being limited to the followingdescription of embodiments. Note that the same portions or portionshaving similar functions are denoted by the same reference signs in thedrawings referred to in the present embodiment, and a repeateddescription thereof will be omitted. Further, the description will begiven using the term “upper” or “lower” for convenience of description,but the vertical direction may be reversed. Further, a “front surface”of a wiring refers to a surface opposite to a surface on which asubstrate is provided as viewed from the wiring in the presentembodiment. A “back surface” of the wiring refers to a surface on theside where the substrate is provided as viewed from the wiring. A “sidesurface” of the wiring refers to a surface located between the “frontsurface” and the “back surface”, the surface facing a lateral side withrespect to a longitudinal direction of the wiring.

A configuration of a wiring board 10 according to the present embodimentwill be described with reference to FIG. 1 or 2.

[Configuration of Wiring Board]

FIG. 1 is a top view illustrating an example of the wiring boardaccording to the present embodiment. FIG. 2 is a cross-sectional viewillustrating an example of the wiring board according to the presentembodiment. FIG. 2(A) is an enlarged cross-sectional view taken along achain line A-A′ of FIG. 1. FIG. 2(B) is an enlarged cross-sectional viewtaken along a chain line B-B′ of FIG. 1. As illustrated in FIG. 1, thewiring board 10 includes a substrate 100, a first wiring 200, and asecond wiring 300. The first wiring 200 and the second wiring 300 arearranged on an upper surface of the substrate 100. Although two firstwirings 200 and one second wiring 300 are arranged in the presentembodiment, the configuration is not limited thereto. It is sufficientthat two or more first wirings 200 and one or more second wirings 300are provided.

As illustrated in FIG. 1, a line-and-space shape in which a plurality oflines extend independently from a first side 102 of the substrate 100toward a second side 104 opposite to the first side 102 (in alongitudinal direction of the first wiring 200, a first direction, andan opposite direction of D2) is illustrated as a planar shape of thefirst wiring 200. As a planar shape of the second wiring 300, a shape inwhich one line extends in a direction orthogonal to a direction in whichthe first wiring 200 extends (a longitudinal direction of the secondwiring 300, a second direction, and a D3 direction) is illustrated. Thatis, the second wiring 300 is orthogonal to the two first wirings 200.Further, the first wiring 200 is longer than the second wiring 300. Whenthe wiring board 10 has a radio wave transmission/reception function,the first wiring 200 has a function as an antenna, and the second wiring300 has a function of connecting the plurality of first wirings 200.Each of the first wirings 200 extends in a direction (a D2 direction)corresponding to a frequency band of the antenna, and each of the secondwirings 300 extends in the direction orthogonal to the first wiring 200(the D3 direction). However, it is sufficient that a plurality of linesintersect or are connected with each other in the planar shape of thefirst wiring 200 and the second wiring 300 without being limited to sucha shape. For example, a direction of the first wiring 200 and adirection of the second wiring 300 may intersect at an acute angle ormay intersect at an obtuse angle. When the plurality of first wirings200 and the plurality of second wirings 300 are arranged, the planarshape thereof have such a repetitive shape. That is, a regular grid ormesh shape is formed by the first wiring 200 extending in the firstdirection and the second wiring 300 extending in the second direction.However, the configuration is not limited thereto, and the repetitiveshape is not necessarily uniform on the substrate 100. Further, thesubstrate 100 is rectangular in FIG. 1, but is not limited to thisshape.

As illustrated in FIG. 2(A), the first wiring 200 has a back surface(first surface) 201 in contact with the substrate 100, and a frontsurface (second surface) 202 facing the opposite side of the backsurface 201. As illustrated in FIG. 2(B), the second wiring 300 has aback surface (third surface) 303 in contact with the substrate 100, anda front surface (fourth surface) 304 facing the opposite side of theback surface 303. As illustrated in FIGS. 1, 2(A), and 2(B), a linewidth of the front surface 304 of the second wiring 300 is smaller thana line width of the front surface 202 of the first wiring 200. Further,a line width of the back surface 303 of the second wiring 300 is smallerthan a line width of the back surface 201 of the first wiring 200. Here,the line width means a width parallel to the upper surface of thesubstrate 100 in a cross section that intersects perpendicularly with adirection in which each wiring extends. That is, the line widths of thefront surface 202 and the back surface 201 of the first wiring 200 inthe present embodiment respectively indicate lengths of the frontsurface 202 and the back surface 201 in the D3 direction, and the linewidths of the front surface 304 and the back surface 303 of the secondwiring 300 respectively indicate lengths of the front surface 304 andthe back surface 303 in the D2 direction. With the arrangement in whichthe line widths of the front surface 304 and the back surface 303 of thesecond wiring 300 are smaller than the line widths of the front surface202 and the back surface 201 of the first wiring 200, respectively, itis possible to suppress the visibility of the spare second wiring 300corresponding to the disconnection of the first wiring 200 or the likewhile maintaining reliability of the first wiring 200 having the radiowave transmission/reception function. Thus, a conductivity andtransparency of the wiring board 10 can be improved. Note that the linewidth of the front surface 304 of the second wiring 300 may be the sameas the line width of the front surface 202 of the first wiring 200without being limited to the above arrangement. Further, the line widthof the back surface 303 of the second wiring 300 may be the same as theline width of the back surface 201 of the first wiring 200.

As illustrated in FIG. 2(A), the line width of the back surface 201 ofthe first wiring 200 is larger than the line width of the front surface202 of the first wiring 200. As illustrated in FIG. 2(B), the line widthof the back surface 303 of the second wiring 300 is larger than the linewidth of the front surface 304 of the second wiring 300. Since the firstwiring 200 and the second wiring 300 are arranged such that the linewidth of the surface in contact with the substrate 100 is larger thanthe line width of the surface facing the side opposite to the surface incontact with the substrate 100, the adhesion between the substrate 100and each of the first wiring 200 and the second wiring 300 can beimproved while suppressing the visibility of the first wiring 200 andthe second wiring 300 in a plan view in the D1 direction. Furthermore, awiring resistance can be suppressed by increasing the area of each crosssection of the first wiring 200 and the second wiring 300 thatintersects perpendicularly with the direction in which each wiringextends. Thus, the transparency, the reliability, and the conductivityof the wiring board 10 can be improved.

As illustrated in FIG. 2(A), the first wiring 200 has a pair of sidesurfaces (ninth and tenth surfaces) 209 and 210 which extend in thedirection of the first wiring 200 and are adjacent to the back surface201. In the first wiring 200, an angle between the back surface 201 andone side surface 209 and an angle between the back surface 201 and theother side surface 210 are acute angles. In the first wiring 200, theangle between the back surface 201 and the one side surface 209 is thesame as the angle between the back surface 201 and the other sidesurface 210. That is, in a cross section that intersects perpendicularlywith a direction in which the first wiring 200 extends, the first wiring200 is line-symmetric about the extending direction (the D2 direction).

As illustrated in FIG. 2(B), the second wiring 300 has a pair of sidesurfaces (fifth and sixth surfaces) 305 and 306 which extend in thedirection of the second wiring 300 and are adjacent to the back surface303. In the second wiring 300, an angle between the back surface 303 andone side surface 305 and an angle between the back surface 303 and theother side surface 306 are acute angles. In the second wiring 300, theangle between the back surface 303 and the one side surface 305 is thesame as the angle between the back surface 303 and the other sidesurface 306. That is, in a cross section that intersects perpendicularlywith the direction in which the second wiring 300 extends, the secondwiring 300 is line-symmetric about the extending direction (the D3direction).

It is sufficient that a material of the first wiring 200 and a materialof the second wiring 300 are conductive metal materials. In the presentembodiment, the material of the first wiring 200 and the material of thesecond wiring 300 are copper, but are not limited thereto. As thematerial of the first wiring 200 and the material of the second wiring300, for example, a metal material (including an alloy) such as gold,silver, copper, platinum, tin, aluminum, iron, and nickel can be used.

In the present embodiment, the line width of the first wiring 200 (theline width of the back surface 201 and the line width of the frontsurface 202) is not particularly limited as long as the above conditionsare satisfied, and can be appropriately selected according to theapplication. For example, the line width of the first wiring 200 can beselected in a range of 0.1 μm or more and 5.0 μm or less. The line widthof the second wiring 300 (the line width of the back surface 303 and theline width of the front surface 304) is not particularly limited as longas the above conditions are satisfied, and can be appropriately selectedaccording to the application. For example, the line width of the secondwiring 300 can be selected in a range of 0.1 μm or more and 5.0 μm orless. Each height of the first wiring 200 and the second wiring 300 isnot particularly limited, and can be appropriately selected according tothe application, and, for example, can be selected in the range of 0.1μm or more and 5.0 μm or less.

Although not illustrated in the drawing, it is preferable that the firstwiring 200 and the second wiring 300 be subjected to a blackeningtreatment on surfaces other than the surface in contact with thesubstrate 100. In particular, it is preferable that the surface facingthe side opposite to the surface in contact with the substrate 100 besubjected to the blackening treatment for each of the first wiring 200and the second wiring 300. In the present embodiment, the front surface202 of the first wiring 200 and the front surface 304 of the secondwiring 300 include copper oxide, which is an oxide film of each wiringmaterial. However, the configuration is not limited thereto, and it ismore preferable that the side surface 209 and the side surface 210 ofthe first wiring 200 and the side surface 305 and the side surface 306of the second wiring 300 be further subjected to the blackeningtreatment. Further, as a method for the blackening treatment, formationcan be performed by a known blackening treatment method such asoxidation, sulfurization, and nickel black plating of the metal wiring.The blackening treatment may be performed by forming a black resin filmor the like. Since the front surfaces of the first wiring 200 and thesecond wiring 300 are subjected to the blackening treatment, it ispossible to suppress light reflection of the first wiring 200 and thesecond wiring 300, and to achieve absorption of external light of thewiring board 10 and contrast improvement.

Although not illustrated in the drawing, an adhesion layer may befurther arranged between the substrate 100 and the first wiring 200 andbetween the substrate 100 and the second wiring 300. As a material ofthe adhesion layer, for example, indium-zinc-oxide (IZO) or the like canbe used. Since the adhesion layer is arranged between the substrate 100and the first wiring 200 and between the substrate 100 and the secondwiring 300, the adhesion between the substrate 100 and the first wiring200 and between the substrate 100 and the second wiring 300 can befurther improved.

It is sufficient that a material of the substrate 100 is a materialhaving transparency and an electrical insulating property in a visiblelight region. In the present embodiment, the material of the substrate100 is polyethylene terephthalate, but is not limited thereto. As thematerial of the substrate 100, it is preferable to use, for example, anorganic insulating material such as a polyester resin such aspolyethylene terephthalate, an acrylic resin such aspomethylmethacrylate, a polycarbonate resin, a polyimide resin, apolyolefin resin such as a cycloolefin polymer, and a cellulosic resinmaterial such as triacetyl cellulose. Further, glass, ceramics, or thelike can be appropriately selected as the material of the substrate 100according to the application. Note that the example in which thesubstrate 100 is constituted by a single layer is illustrated, but astructure in which a plurality of base materials or layers are stackedmay be adopted without being limited thereto. Further, the substrate 100may be in the form of a film or a plate. Thus, a thickness of thesubstrate 100 is not particularly limited, and can be appropriatelyselected according to the application.

As described above, the wiring board 10 according to the presentembodiment is arranged such that the line widths of the back surface 303and the front surface 304 of the second wiring 300 are smaller than theline widths of the back surface 201 and the front surface 202 of thefirst wiring 200, respectively, on the substrate 100, and thus, it ispossible to suppress the visibility of the second wiring 300 in a planview in the D1 direction while maintaining the reliability of the firstwiring 200 having the radio wave transmission/reception function. Sincethe first wiring 200 and the second wiring 300 are arranged such thatthe line width of the surface in contact with the substrate 100 islarger than the surface facing the side opposite to the surface incontact with the substrate 100, the adhesion between the substrate 100and each of the first wiring 200 and the second wiring 300 can beimproved while suppressing the visibility of the first wiring 200 andthe second wiring 300 in a plan view in the D1 direction. Furthermore, awiring resistance can be suppressed by increasing each cross-sectionalarea of the first wiring 200 and the second wiring 300 that intersectsperpendicularly with the direction in which each wiring extends. Thus,the transparency, the reliability, and the conductivity of the wiringboard 10 can be improved.

The wiring board 10 according to the present embodiment can be mountedon a display device as a wireless communication module by beingconnected to a wireless communication circuit. The wiring board 10 isarranged on an upper surface of a display region such that the substrate100 faces the display region of the display device so that it ispossible to suppress the visibility of the first wiring 200 and thesecond wiring 300 in a plan view in the D1 direction. Thus, it ispossible to provide the display device including the wiring board havingthe radio wave transmission/reception function with improvedtransparency, reliability, and conductivity.

When the wiring board 10 has the radio wave transmission/receptionfunction, the wiring board 10 may have any function of a telephoneantenna, a WiFi antenna, a 3G antenna, a 4G antenna, an LTE antenna, aBluetooth (registered trademark) antenna, and an NFC antenna.Alternatively, the wiring board 10 does not necessarily have the radiowave transmission/reception function, and in this case, the wiring board10 may serve a function, for example, hovering (a function that enablesoperation without requiring a user to directly touch a display),fingerprint authentication, a heater, noise cut (shield), or the like.

Next, various modifications of the wiring board according to the presentembodiment will be described.

<First Modification>

In the mode illustrated in FIGS. 1 and 2, the second wiring 300 isline-symmetric about the longitudinal direction (the D3 direction) inthe cross section that intersects perpendicularly with the direction inwhich the second wiring 300 extends. In the present modification,however, a second wiring 300 a is asymmetric about a longitudinaldirection (D3 direction) in a cross section that intersectsperpendicularly with a direction in which the second wiring 300 aextends.

A configuration of a wiring board 10 a according to the presentmodification will be described with reference to FIG. 3. Here, theconfiguration of the wiring board 10 a according to the presentmodification is the same as the configuration of the wiring board 10illustrated in FIGS. 1 and 2 except for the cross-sectional shape of thesecond wiring 300. Thus, detailed descriptions of the same portions asthose in the mode illustrated in FIGS. 1 and 2 will be omitted.

[Configuration of Wiring Board]

FIG. 3 is a cross-sectional view illustrating an example of the wiringboard according to the present modification. The wiring board 10 aaccording to the present modification includes a substrate 100 a, afirst wiring 200 a, and the second wiring 300 a, which is similar to themode illustrated in FIG. 1. FIG. 3(A) is an enlarged cross-sectionalview taken along a chain line A-A′ of FIG. 1. FIG. 3(B) is an enlargedcross-sectional view taken along a chain line B-B′ of FIG. 1.

As illustrated in FIG. 3(A), the first wiring 200 a has a back surface(first surface) 201 a in contact with the substrate 100 a, and a frontsurface (second surface) 202 a facing the opposite side of the backsurface 201 a. As illustrated in FIG. 3(B), the second wiring 300 a hasa back surface (third surface) 303 a in contact with the substrate 100a, and a front surface (fourth surface) 304 a facing the opposite sideof the back surface 303 a. As illustrated in FIGS. 3(A) and 3(B), a linewidth of the front surface 304 a of the second wiring 300 a is smallerthan a line width of the front surface 202 a of the first wiring 200 a.Further, a line width of the back surface 303 a of the second wiring 300a is smaller than a line width of the back surface 201 a of the firstwiring 200 a. With the arrangement in which the line widths of the frontsurface 304 a and the back surface 303 a of the second wiring 300 a aresmaller than the line widths of the front surface 202 a and the backsurface 201 a of the first wiring 200 a, respectively, it is possible tosuppress the visibility of the spare second wiring 300 a correspondingto the disconnection of the first wiring 200 a or the like whilemaintaining reliability of the first wiring 200 a having a radio wavetransmission/reception function. Thus, a conductivity and transparencyof the wiring board 10 a can be improved.

As illustrated in FIG. 3(A), the line width of the back surface 201 a ofthe first wiring 200 a is larger than the line width of the frontsurface 202 a of the first wiring 200 a. As illustrated in FIG. 3(B),the line width of the back surface 303 a of the second wiring 300 a islarger than the line width of the front surface 304 a of the secondwiring 300 a. Since the first wiring 200 a and the second wiring 300 aare arranged such that the line width of the surface in contact with thesubstrate 100 a is larger than the line width of the surface facing theside opposite to the surface in contact with the substrate 100 a, theadhesion between the substrate 100 a and each of the first wiring 200 aand the second wiring 300 a can be improved while suppressing thevisibility of the first wiring 200 a and the second wiring 300 a in aplan view in a D1 direction. Furthermore, a wiring resistance can besuppressed by increasing the area of each cross section of the firstwiring 200 a and the second wiring 300 a that intersects perpendicularlywith the direction in which each wiring extends. Thus, the transparency,the reliability, and the conductivity of the wiring board 10 a can beimproved.

As illustrated in FIG. 3(A), the first wiring 200 a has a pair of sidesurfaces (ninth and tenth surfaces) 209 a and 210 a which extend in thedirection of the first wiring 200 a and are adjacent to the back surface201 a. In the first wiring 200 a, an angle between the back surface 201a and one side surface 209 a and an angle between the back surface 201 aand the other side surface 210 a are acute angles. In the first wiring200 a, the angle between the back surface 201 a and the pair of sidesurfaces 209 a is the same as the angle between the back surface 201 aand the other side surface 210 a. That is, in a cross section thatintersects perpendicularly with a direction in which the first wiring200 a extends, the first wiring 200 a is line-symmetric about theextending direction (the D2 direction).

As illustrated in FIG. 3(B), the second wiring 300 a has a pair of sidesurfaces (fifth and sixth surfaces) 305 a and 306 a which extend in thedirection of the second wiring 300 a and are adjacent to the backsurface 303 a. In the second wiring 300 a, an angle between the backsurface 303 a and one side surface 305 a and an angle between the backsurface 303 a and the other side surface 306 a are acute angles. In thesecond wiring 300 a, the angle between the back surface 303 a and theother side surface 306 a is smaller than the angle between the backsurface 303 a and the one side surface 305 a. That is, in a crosssection that intersects perpendicularly with the direction in which thesecond wiring 300 a extends, the second wiring 300 a is asymmetric aboutthe extending direction (the D3 direction). With the arrangement inwhich the angle between the back surface 303 a and the other sidesurface 306 a is smaller than the angle between the back surface 303 aand the one side surface 305 a in the second wiring 300 a, the linewidth of the back side 303 a becomes large, and it is possible toimprove the adhesion between the substrate 100 a and the second wiring300 a while suppressing the visibility of the one side surface 305 a ofthe second wiring 300 a in a plan view in the D1 direction. Furthermore,a wiring resistance can be suppressed by increasing a cross-sectionalarea of the second wiring 300 a that intersects perpendicularly with thedirection in which the wiring extends. Thus, the transparency, thereliability, and the conductivity of the wiring board 10 a can beimproved.

As described above, the wiring board 10 a according to the presentmodification is arranged such that the line widths of the back surface303 a and the front surface 304 a of the second wiring 300 a are smallerthan the line widths of the back surface 201 a and the front surface 202a of the first wiring 200 a, respectively, on the substrate 100 a, andthus, it is possible to suppress the visibility of the second wiring 300a in a plan view in the D1 direction while maintaining the reliabilityof the first wiring 200 a having the radio wave transmission/receptionfunction. Since the first wiring 200 a and the second wiring 300 a arearranged such that the line width of the surface in contact with thesubstrate 100 a is larger than the surface facing the side opposite tothe surface in contact with the substrate 100 a, the adhesion betweenthe substrate 100 a and each of the first wiring 200 a and the secondwiring 300 a can be improved while suppressing the visibility of thefirst wiring 200 a and the second wiring 300 a in a plan view in a D1direction. With the arrangement in which the angle between the backsurface 303 a and the other side surface 306 a is smaller than the anglebetween the back surface 303 a and the one side surface 305 a in thesecond wiring 300 a, it is possible to improve the adhesion between thesubstrate 100 a and the second wiring 300 a while suppressing thevisibility of the one side surface 305 a of the second wiring 300 a in aplan view in the D1 direction. Furthermore, a wiring resistance can besuppressed by increasing each cross-sectional area of the first wiring200 a and the second wiring 300 a that intersects perpendicularly withthe direction in which each wiring extends. Thus, the transparency, thereliability, and the conductivity of the wiring board 10 a can beimproved.

The wiring board 10 a according to the present modification can bemounted on a display device as a wireless communication module by beingconnected to a wireless communication circuit. The wiring board 10 a isarranged on an upper surface of a display region such that the substrate100 a faces the display region of the display device so that it ispossible to suppress the visibility of the first wiring 200 a and thesecond wiring 300 a in a plan view in the D1 direction. The wiring board10 a is arranged such that a direction of the first wiring 200 a is avertical direction of the display region and the one side surface 305 aof the second wiring 300 a is in the upper direction of the displayregion (light incident direction) so that the reflection of light by theother side surface 306 a of the second wiring 300 a can be suppressed.Thus, it is possible to provide the display device including the wiringboard having the radio wave transmission/reception function withimproved transparency, reliability, and conductivity.

<Second Modification>

In the mode illustrated in FIGS. 1 and 2, the second wiring 300 isline-symmetric with respect to the longitudinal direction (the D3direction) in the cross section that intersects perpendicularly with thedirection in which the second wiring 300 extends. In the presentmodification, however, a second wiring 300 b is asymmetric about alongitudinal direction (D3 direction) in a cross section that intersectsperpendicularly with a direction in which the second wiring 300 bextends.

A configuration of a wiring board 10 b according to the presentmodification will be described with reference to FIG. 4. Here, theconfiguration of the wiring board 10 b according to the presentmodification is the same as the configuration of the wiring board 10illustrated in FIGS. 1 and 2 except for the cross-sectional shape of thesecond wiring 300. Thus, detailed descriptions of the same portions asthose in the mode illustrated in FIGS. 1 and 2 will be omitted.

[Configuration of Wiring Board]

FIG. 4 is a cross-sectional view illustrating an example of the wiringboard according to the present modification. The wiring board 10 baccording to the present modification includes a substrate 100 b, afirst wiring 200 b, and the second wiring 300 b, which is similar to themode illustrated in FIG. 1. FIG. 4(A) is an enlarged cross-sectionalview taken along the chain line A-A′ of FIG. 1. FIG. 4(B) is an enlargedcross-sectional view taken along the chain line B-B′ of FIG. 1.

As illustrated in FIG. 4(A), the first wiring 200 b has a back surface(first surface) 201 b in contact with the substrate 100 b, and a frontsurface (second surface) 202 b facing the opposite side of the backsurface 201 b. As illustrated in FIG. 4(B), the second wiring 300 b hasa back surface (third surface) 303 b in contact with the substrate 100b, and a front surface (fourth surface) 304 b facing the opposite sideof the back surface 303 b. As illustrated in FIGS. 4(A) and 4(B), a linewidth of the front surface 304 b of the second wiring 300 b is smallerthan a line width of the front surface 202 b of the first wiring 200 b.Further, a line width of the back surface 303 b of the second wiring 300b is smaller than a line width of the back surface 201 b of the firstwiring 200 b. With the arrangement in which the line widths of the frontsurface 304 b and the back surface 303 b of the second wiring 300 b aresmaller than the line widths of the front surface 202 b and the backsurface 201 b of the first wiring 200 b, respectively, it is possible tosuppress the visibility of the spare second wiring 300 b correspondingto the disconnection of the first wiring 200 b or the like whilemaintaining reliability of the first wiring 200 b having a radio wavetransmission/reception function. Thus, a conductivity and transparencyof the wiring board 10 b can be improved.

As illustrated in FIG. 4(A), the line width of the back surface 201 b ofthe first wiring 200 b is larger than the line width of the frontsurface 202 b of the first wiring 200 b. As illustrated in FIG. 4(B),the line width of the back surface 303 b of the second wiring 300 b islarger than the line width of the front surface 304 b of the secondwiring 300 b. Since the first wiring 200 b and the second wiring 300 bare arranged such that the line width of the surface in contact with thesubstrate 100 b is larger than the line width of the surface facing theside opposite to the surface in contact with the substrate 100 b, theadhesion between the substrate 100 b and each of the first wiring 200 band the second wiring 300 b can be improved while suppressing thevisibility of the first wiring 200 b and the second wiring 300 b in aplan view in the D1 direction. Furthermore, a wiring resistance can besuppressed by increasing the area of each cross section of the firstwiring 200 b and the second wiring 300 b that intersects perpendicularlywith the direction in which each wiring extends. Thus, the transparency,the reliability, and the conductivity of the wiring board 10 b can beimproved.

As illustrated in FIG. 4(A), the first wiring 200 b has a pair of sidesurfaces (ninth and tenth surfaces) 209 b and 210 b which extend in thedirection of the first wiring 200 b and are adjacent to the back surface201 b. In the first wiring 200 b, an angle between the back surface 201b and one side surface 209 b and an angle between the back surface 201 band the other side surface 210 b are acute angles. In the first wiring200 b, the angle between the back surface 201 b and the one side surface209 b is the same as the angle between the back surface 201 b and theother side surface 210 b. That is, in a cross section that intersectsperpendicularly with a direction in which the first wiring 200 bextends, the first wiring 200 b is line-symmetric about the extendingdirection (the D2 direction).

As illustrated in FIG. 4(B), the second wiring 300 b has a pair of sidesurfaces (fifth and sixth surfaces) 305 b and 306 b which extend in thedirection of the second wiring 300 b and are adjacent to the backsurface 303 b. In the second wiring 300 b, an angle between the backsurface 303 b and one side surface 305 b and an angle between the backsurface 303 b and the other side surface 306 b are acute angles. In thesecond wiring 300 b, the angle between the back surface 303 b and theother side surface 306 b is smaller than the angle between the backsurface 303 b and the one side surface 305 b. The one side surface 305 bof the second wiring 300 b according to the present modification isrecessed inward (toward the negative side in the D2 direction). The oneside surface 305 b includes an upper side surface (seventh surface) 307b adjacent to the front surface 304 b. In FIG. 4(B), an angle betweenthe front surface 304 b and the upper side surface 307 b is about 90°.However, the configuration is not limited thereto, and it is sufficientfor the angle between the front surface 304 b and the upper side surface307 b to be smaller than an external angle of the angle between the backsurface 303 b and the one side surface 305 b (an angle obtained bysubtracting the angle between the back surface 303 b and the one sidesurface 305 b from 180°). The angle between the front surface 304 b andthe upper side surface 307 b is preferably in a range of 60° or more and90° or less. That is, the one side surface 305 b of the second wiring300 b includes a shape (the upper side surface 307 b) that is connectedto the front surface 304 b at an angle smaller than the external angleof the angle between the back surface 303 b and the one side surface 305b. However, the configuration is not limited thereto, and the one sidesurface 305 b may further include a different surface, and therespective surfaces forming the one side surface 305 b may form a corner(intersection line) or may be continuously connected by a curvedsurface. In a cross section that intersects perpendicularly with adirection in which the second wiring 300 b extends, the second wiring300 b is asymmetric about the extending direction (the D3 direction).

With the arrangement in which the angle between the back surface 303 band the other side surface 306 b is smaller than the angle between theback surface 303 b and the one side surface 305 b in the second wiring300 b, the line width of the back side 303 b becomes large, and it ispossible to improve the adhesion between the substrate 100 b and thesecond wiring 300 b while suppressing the visibility of the one sidesurface 305 b of the second wiring 300 b in a plan view in the D1direction. Since the angle between the front surface 304 b and the upperside surface 307 b is smaller than the external angle of the anglebetween the back surface 303 b and the one side surface 305 b in thesecond wiring 300 b, the visibility of the upper side surface 307 b ofthe second wiring 300 b in a plan view in the D1 direction can besuppressed. Furthermore, a wiring resistance can be suppressed byincreasing a cross-sectional area of the second wiring 300 b thatintersects perpendicularly with the direction in which the wiringextends. Thus, the transparency, the reliability, and the conductivityof the wiring board 10 b can be improved.

As described above, the wiring board 10 b according to the presentmodification is arranged such that the line widths of the back surface303 b and the front surface 304 b of the second wiring 300 b are smallerthan the line widths of the back surface 201 b and the front surface 202b of the first wiring 200 b, respectively, on the substrate 100 b, andthus, it is possible to suppress the visibility of the second wiring 300b in a plan view in the D1 direction while maintaining the reliabilityof the first wiring 200 b having the radio wave transmission/receptionfunction. Since the first wiring 200 b and the second wiring 300 b arearranged such that the line width of the surface in contact with thesubstrate 100 b is larger than the surface facing the side opposite tothe surface in contact with the substrate 100 b, the adhesion betweenthe substrate 100 b and each of the first wiring 200 b and the secondwiring 300 b can be improved while suppressing the visibility of thefirst wiring 200 b and the second wiring 300 b in a plan view in the D1direction. With the arrangement in which the angle between the backsurface 303 b and the other side surface 306 b is smaller than the anglebetween the back surface 303 b and the one side surface 305 b in thesecond wiring 300 b, it is possible to improve the adhesion between thesubstrate 100 b and the second wiring 300 b while suppressing thevisibility of the one side surface 305 b of the second wiring 300 b in aplan view in the D1 direction. Since the angle between the front surface304 b and the upper side surface 307 b is smaller than the externalangle of the angle between the back surface 303 b and the one sidesurface 305 b in the second wiring 300 b, the visibility of the upperside surface 307 b of the second wiring 300 b in a plan view in the D1direction can be suppressed. Furthermore, a wiring resistance can besuppressed by increasing each cross-sectional area of the first wiring200 b and the second wiring 300 b that intersects perpendicularly withthe direction in which each wiring extends. Thus, the transparency, thereliability, and the conductivity of the wiring board 10 b can beimproved.

The wiring board 10 b according to the present modification can bemounted on a display device as a wireless communication module by beingconnected to a wireless communication circuit. The wiring board 10 b isarranged on an upper surface of a display region such that the substrate100 b faces the display region of the display device so that it ispossible to suppress the visibility of the first wiring 200 b and thesecond wiring 300 b in a plan view in the D1 direction. The wiring board10 b is arranged such that a direction of the first wiring 200 b is avertical direction of the display region and the upper side surface 307b of the second wiring 300 b is in the upper direction of the displayregion (light incident direction) so that the reflection of light by theother side surface 306 b of the second wiring 300 b can be suppressed.Thus, it is possible to provide the display device including the wiringboard having the radio wave transmission/reception function withimproved transparency, reliability, and conductivity.

<Third Modification>

In the mode illustrated in FIGS. 1 and 2, the second wiring 300 isline-symmetric with respect to the longitudinal direction (the D3direction) in the cross section that intersects perpendicularly with thedirection in which the second wiring 300 extends. In the presentmodification, however, a second wiring 300 c is asymmetric about alongitudinal direction (D3 direction) in a cross section that intersectsperpendicularly with a direction in which the second wiring 300 cextends.

A configuration of a wiring board 10 c according to the presentmodification will be described with reference to FIG. 5. Here, theconfiguration of the wiring board 10 c according to the presentmodification is the same as the configuration of the wiring board 10illustrated in FIGS. 1 and 2 except for the cross-sectional shapes ofthe first wiring 200 and the second wiring 300. Thus, detaileddescriptions of the same portions as those in the mode illustrated inFIGS. 1 and 2 will be omitted.

[Configuration of Wiring Board]

FIG. 5 is a cross-sectional view illustrating an example of the wiringboard according to the present modification. The wiring board 10 caccording to the present modification includes a substrate 100 c, afirst wiring 200 c, and the second wiring 300 c, which is similar to themode illustrated in FIG. 1. FIG. 5(A) is an enlarged cross-sectionalview taken along the chain line A-A′ of FIG. 1. FIG. 5(B) is an enlargedcross-sectional view taken along the chain line B-B′ of FIG. 1.

As illustrated in FIG. 5(A), the first wiring 200 c has a back surface(first surface) 201 c in contact with the substrate 100 c, and a frontsurface (second surface) 202 c facing the opposite side of the backsurface 201 c. As illustrated in FIG. 5(B), the second wiring 300 c hasa back surface (third surface) 303 c in contact with the substrate 100c, and a front surface (fourth surface) 304 c facing the opposite sideof the back surface 303 c. As illustrated in FIGS. 5(A) and 5(B), a linewidth of the front surface 304 c of the second wiring 300 c is smallerthan a line width of the front surface 202 c of the first wiring 200 c.Further, a line width of the back surface 303 c of the second wiring 300c is smaller than a line width of the back surface 201 c of the firstwiring 200 c. With the arrangement in which the line widths of the frontsurface 304 c and the back surface 303 c of the second wiring 300 c aresmaller than the line widths of the front surface 202 c and the backsurface 201 c of the first wiring 200 c, respectively, it is possible tosuppress the visibility of the spare second wiring 300 c correspondingto the disconnection of the first wiring 200 c or the like whilemaintaining reliability of the first wiring 200 c having a radio wavetransmission/reception function. Thus, a conductivity and transparencyof the wiring board 10 c can be improved.

As illustrated in FIG. 5(A), the line width of the back surface 201 c ofthe first wiring 200 c is larger than the line width of the frontsurface 202 c of the first wiring 200 c. As illustrated in FIG. 5(B),the line width of the back surface 303 c of the second wiring 300 c islarger than the line width of the front surface 304 c of the secondwiring 300 c. Since the first wiring 200 c and the second wiring 300 care arranged such that the line width of the surface in contact with thesubstrate 100 c is larger than the line width of the surface facing theside opposite to the surface in contact with the substrate 100 c, theadhesion between the substrate 100 c and each of the first wiring 200 cand the second wiring 300 c can be improved while suppressing thevisibility of the first wiring 200 c and the second wiring 300 c in aplan view in the D1 direction. Furthermore, a wiring resistance can besuppressed by increasing the area of each cross section of the firstwiring 200 c and the second wiring 300 c that intersects perpendicularlywith the direction in which each wiring extends. Thus, the transparency,the reliability, and the conductivity of the wiring board 10 c can beimproved.

As illustrated in FIG. 5(A), the first wiring 200 c has a pair of sidesurfaces (ninth and tenth surfaces) 209 c and 210 c which extend in thedirection of the first wiring 200 c and are adjacent to the back surface201 c. In the first wiring 200 c, an angle between the back surface 201c and one side surface 209 c and an angle between the back surface 201 cand the other side surface 210 c are acute angles. In the first wiring200 c, the angle between the back surface 201 c and the one side surface209 c is the same as the angle between the back surface 201 c and theother side surface 210 c. The one side surface 209 c of the first wiring200 c according to the present modification is recessed inward (towardthe positive side in the D3 direction). The one side surface 209 cincludes an upper side surface (eleventh surface) 211 c adjacent to thefront surface 202 c. The other side surface 210 c of the first wiring200 c is recessed inward (toward the negative side in the D3 direction).The other side surface 210 c includes an upper side surface (twelfthsurface) 212 c adjacent to the front surface 202 c. In FIG. 5(A), anangle between the front surface 202 c and the upper side surface 211 cand an angle between the front surface 202 c and the upper side surface212 c are approximately 90°. However, the configuration is not limitedthereto, and the angle between the front surface 202 c and the upperside surface 211 c may be smaller than an external angle of the anglebetween the back surface 201 c and the one side surface 209 c. The anglebetween the front surface 202 c and the upper side surface 211 c ispreferably in a range of 60° or more and 90° or less. It is sufficientfor the angle between the front surface 202 c and the upper side surface212 c to be smaller than the external angle of the angle between theback surface 201 c and the other side surface 210 c. The angle betweenthe front surface 202 c and the upper side surface 212 c is preferablyin a range of 60° or more and 90° or less. That is, the one side surface209 c of the first wiring 200 c includes a shape (the upper side surface211 c) that is connected to the front surface 202 c at an angle smallerthan the external angle of the angle between the back surface 201 c andthe one side surface 209 c. The other side surface 210 c of the firstwiring 200 c includes a shape (the upper side surface 212 c) that isconnected to the front surface 202 c at an angle smaller than theexternal angle of the angle between the back surface 201 c and the otherside surface 210 c. However, the configuration is not limited thereto,and the one side surface 209 c and the other side surface 210 c mayfurther include different surfaces, and the respective surfaces formingthe one side surface 209 c and the other side surface 210 c may form acorner (intersection line) or may be continuously connected by a curvedsurface. That is, in a cross section that intersects perpendicularlywith a direction in which the first wiring 200 c extends, the firstwiring 200 c is line-symmetric about the extending direction (the D2direction). Since the angle between the front surface 202 c and theupper side surface 211 c is smaller than the external angle of the anglebetween the back surface 201 c and the one side surface 209 c, and theangle between the front surface 202 c and the upper side surface 212 cis smaller than the external angle of the angle between the back surface201 c and the other side surface 210 c in the first wiring 200 c, it ispossible to suppress the visibility of the upper side surface 211 c andthe upper side surface 212 c of the first wiring 200 c in a plan view inthe D1 direction. Furthermore, a wiring resistance can be suppressed byincreasing a cross-sectional area of the first wiring 200 c thatintersects perpendicularly with the direction in which the wiringextends. Thus, the transparency, the reliability, and the conductivityof the wiring board 10 c can be improved.

As illustrated in FIG. 5(B), the second wiring 300 c has a pair of sidesurfaces (fifth and sixth surfaces) 305 c and 306 c which extend in thedirection of the second wiring 300 c and are adjacent to the backsurface 303 c. In the second wiring 300 c, an angle between the backsurface 303 c and one side surface 305 c and an angle between the backsurface 303 c and the other side surface 306 c are acute angles. In thesecond wiring 300 c, the angle between the back surface 303 c and theother side surface 306 c is smaller than the angle between the backsurface 303 c and the one side surface 305 c. The one side surface 305 cof the second wiring 300 c according to the present modification isrecessed inward (toward the negative side in the D2 direction). The oneside surface 305 c includes an upper side surface (seventh surface) 307c adjacent to the front surface 304 c. The other side surface 306 c ofthe second wiring 300 c is recessed inward (toward the positive side inthe D2 direction). The other side surface 306 c includes an upper sidesurface (eighth surface) 308 c adjacent to the front surface 304 c. InFIG. 5(B), an angle between the front surface 304 c and the upper sidesurface 307 c and an angle between the front surface 304 c and the upperside surface 308 c are approximately 90°. However, the configuration isnot limited thereto, and the angle between the front surface 304 c andthe upper side surface 307 c may be smaller than an external angle ofthe angle between the back surface 303 c and the one side surface 305 c.The angle between the front surface 304 c and the upper side surface 307c is preferably in a range of 60° or more and 90° or less. It issufficient for the angle between the front surface 304 c and the upperside surface 308 c to be smaller than the external angle of the anglebetween the back surface 303 c and the other side surface 306 c. Theangle between the front surface 304 c and the upper side surface 308 cis preferably in a range of 60° or more and 90° or less. That is, theone side surface 305 c of the second wiring 300 c includes a shape (theupper side surface 307 c) that is connected to the front surface 304 cat an angle smaller than the external angle of the angle between theback surface 303 c and the one side surface 305 c. The other sidesurface 306 c of the second wiring 300 c includes a shape (the upperside surface 308 c) that is connected to the front surface 304 c at anangle smaller than the external angle of the angle between the backsurface 303 c and the other side surface 306 c. However, theconfiguration is not limited thereto, and the one side surface 305 c andthe other side surface 306 c may further include different surfaces, andthe respective surfaces forming the one side surface 305 c and the otherside surface 306 c may form a corner (intersection line) or may becontinuously connected by a curved surface. In a cross section thatintersects perpendicularly with a direction in which the second wiring300 c extends, the second wiring 300 c is asymmetric about the extendingdirection (the D3 direction). With the arrangement in which the anglebetween the back surface 303 c and the other side surface 306 c issmaller than the angle between the back surface 303 c and the one sidesurface 305 c in the second wiring 300 c, the line width of the backside 303 c becomes large, and it is possible to improve the adhesionbetween the substrate 100 c and the second wiring 300 c whilesuppressing the visibility of the one side surface 305 c of the secondwiring 300 c in a plan view in the D1 direction. Since the angle betweenthe front surface 304 c and the upper side surface 307 c is smaller thanthe external angle of the angle between the back surface 303 c and theone side surface 305 c, and the angle between the front surface 304 cand the upper side surface 308 c is smaller than the external angle ofthe angle between the back surface 303 c and the other side surface 306c in the second wiring 300 c, it is possible to suppress the visibilityof the upper side surface 307 c and the upper side surface 308 c of thesecond wiring 300 c in a plan view in the D1 direction. Furthermore, awiring resistance can be suppressed by increasing a cross-sectional areaof the second wiring 300 c that intersects perpendicularly with thedirection in which the wiring extends. Thus, the transparency, thereliability, and the conductivity of the wiring board 10 c can beimproved.

As described above, the wiring board 10 c according to the presentmodification is arranged such that the line width of the front surface304 c of the second wiring 300 c of the substrate 100 c is smaller thanthe line width of the front surface 202 c of the first wiring 200 c, andthus, it is possible to suppress the visibility of the second wiring 300c in a plan view in the D1 direction while maintaining the reliabilityof the first wiring 200 c having the radio wave transmission/receptionfunction. Since the first wiring 200 c and the second wiring 300 c arearranged such that the line width of the surface in contact with thesubstrate 100 c is larger than the surface facing the side opposite tothe surface in contact with the substrate 100 c, the adhesion betweenthe substrate 100 c and each of the first wiring 200 c and the secondwiring 300 c can be improved while suppressing the visibility of thefirst wiring 200 c and the second wiring 300 c in a plan view in the D1direction. Since the angle between the front surface 202 c and the upperside surface 211 c is smaller than the external angle of the anglebetween the back surface 201 c and the one side surface 209 c, and theangle between the front surface 202 c and the upper side surface 212 cis smaller than the external angle of the angle between the back surface201 c and the other side surface 210 c in the first wiring 200 c, it ispossible to suppress the visibility of the upper side surface 211 c andthe upper side surface 212 c of the first wiring 200 c in a plan view inthe D1 direction. With the arrangement in which the angle between theback surface 303 c and the other side surface 306 c is smaller than theangle between the back surface 303 c and the one side surface 305 c inthe second wiring 300 c, it is possible to improve the adhesion betweenthe substrate 100 c and the second wiring 300 c while suppressing thevisibility of the one side surface 305 c of the second wiring 300 c in aplan view in the D1 direction. Since the angle between the front surface304 c and the upper side surface 307 c is smaller than the externalangle of the angle between the back surface 303 c and the one sidesurface 305 c, and the angle between the front surface 304 c and theupper side surface 308 c is smaller than the external angle of the anglebetween the back surface 303 c and the other side surface 306 c in thesecond wiring 300 c, it is possible to suppress the visibility of theupper side surface 307 c and the upper side surface 308 c of the secondwiring 300 c in a plan view in the D1 direction. Furthermore, a wiringresistance can be suppressed by increasing each cross-sectional area ofthe first wiring 200 c and the second wiring 300 c that intersectsperpendicularly with the direction in which each wiring extends. Thus,the transparency, the reliability, and the conductivity of the wiringboard 10 c can be improved.

Further, since the side surfaces 209 c and 210 c of the first wiring 200c are recessed inward and the side surfaces 305 c and 306 c of thesecond wiring 300 c are recessed inward according to the presentmodification, it is possible to suppress the maximum width as the firstwiring 200 c and the second wiring 300 c are viewed at an obliqueviewing angle. As a result, for example, it is possible to make thefirst wiring 200 c and the second wiring 300 c less visible on the frontsurface of the display, and to make it difficult for a user to visuallyrecognize the first wiring 200 c and the second wiring 300 c with anaked eye. Further, in general, when an alternating current is appliedto the wiring, it becomes more difficult for the current to flow to acentral portion of the wiring as a frequency becomes higher so that thecurrent flows on the outside surface of the wiring (skin effect). In thepresent modification, it becomes possible to cause the current to flowover a wide region of the cross sections of the first wiring 200 c andthe second wiring 300 c by recessing the respective side surfaces of thefirst wiring 200 c and the second wiring 300 c. Thus, the cross sectionsof the first wiring 200 c and the second wiring 300 c can be usedefficiently. Furthermore, since the respective side surfaces of thefirst wiring 200 c and the second wiring 300 c are recessed, light thatis incident obliquely to the D1 direction is hardly reflected in the D1direction so that it is possible to make it difficult to recognize thefirst wiring 200 c and the second wiring 300 c with the naked eye.

The wiring board 10 c according to the present modification can bemounted on a display device as a wireless communication module by beingconnected to a wireless communication circuit. The wiring board 10 c isarranged on an upper surface of a display region such that the substrate100 c faces the display region of the display device so that it ispossible to suppress the visibility of the first wiring 200 c and thesecond wiring 300 c in a plan view in the D1 direction. The wiring board10 c is arranged such that a direction of the first wiring 200 is avertical direction of the display region and the upper side surface 307c of the second wiring 300 c is in the upper direction of the displayregion (light incident direction) so that the reflection of light by theother side surface 306 c of the second wiring 300 c can be suppressed.Thus, it is possible to provide the display device including the wiringboard having the radio wave transmission/reception function withimproved transparency, reliability, and conductivity.

<Fourth Modification>

In the mode illustrated in FIGS. 1 and 2, the second wiring 300 isline-symmetric with respect to the longitudinal direction (the D3direction) in the cross section that intersects perpendicularly with thedirection in which the second wiring 300 extends. In the presentmodification, however, a second wiring 300 d is asymmetric about alongitudinal direction (D3 direction) in a cross section that intersectsperpendicularly with a direction in which the second wiring 300 dextends.

A configuration of a wiring board 10 d according to the presentmodification will be described with reference to FIG. 6. Here, theconfiguration of the wiring board 10 d according to the modification isthe same as the configuration of the wiring board 10 illustrated inFIGS. 1 and 2 except for the cross-sectional shapes of the first wiring200 and the second wiring 300. Thus, detailed descriptions of the sameportions as those in the mode illustrated in FIGS. 1 and 2 will beomitted.

[Configuration of Wiring Board]

FIG. 6 is a cross-sectional view illustrating an example of the wiringboard according to the present modification. The wiring board 10 daccording to the present modification includes a substrate 100 d, afirst wiring 200 d, and the second wiring 300 d, which is similar to themode illustrated in FIG. 1. FIG. 6(A) is an enlarged cross-sectionalview taken along the chain line A-A′ of FIG. 1. FIG. 6(B) is an enlargedcross-sectional view taken along the chain line B-B′ of FIG. 1.

As illustrated in FIG. 6(A), the first wiring 200 d has a back surface(first surface) 201 d in contact with the substrate 100 d, and a frontsurface (second surface) 202 d facing the opposite side of the backsurface 201 d. As illustrated in FIG. 6(B), the second wiring 300 d hasa back surface (third surface) 303 d in contact with the substrate 100 dand a front surface (fourth surface) 304 d facing the opposite side ofthe back surface 303 d. As illustrated in FIGS. 6(A) and 6(B), a linewidth of the front surface 304 d of the second wiring 300 d is smallerthan a line width of the front surface 202 d of the first wiring 200 d.A line width of the back surface 303 d of the second wiring 300 d issmaller than a line width of the back surface 201 d of the first wiring200 d. With the arrangement in which the line widths of the frontsurface 304 d and the back surface 303 d of the second wiring 300 d aresmaller than the line widths of the front surface 202 d and the backsurface 201 d of the first wiring 200 d, respectively, it is possible tosuppress the visibility of the spare second wiring 300 d correspondingto the disconnection of the first wiring 200 d or the like whilemaintaining reliability of the first wiring 200 d having a radio wavetransmission/reception function. Thus, a conductivity and transparencyof the wiring board 10 d can be improved.

As illustrated in FIG. 6(A), the line width of the back surface 201 d ofthe first wiring 200 d is larger than the line width of the frontsurface 202 d of the first wiring 200 d. As illustrated in FIG. 6(B),the line width of the back surface 303 d of the second wiring 300 d islarger than the line width of the front surface 304 d of the secondwiring 300 d. Since the first wiring 200 d and the second wiring 300 dare arranged such that the line width of the surface in contact with thesubstrate 100 d is larger than the line width of the surface facing theside opposite to the surface in contact with the substrate 100 d, theadhesion between the substrate 100 d and each of the first wiring 200 dand the second wiring 300 d can be improved while suppressing thevisibility of the first wiring 200 d and the second wiring 300 d in aplan view in the D1 direction. Furthermore, a wiring resistance can besuppressed by increasing the area of each cross section of the firstwiring 200 d and the second wiring 300 d that intersects perpendicularlywith the direction in which each wiring extends. Thus, the transparency,the reliability, and the conductivity of the wiring board 10 d can beimproved.

As illustrated in FIG. 6(A), the first wiring 200 d has a pair of sidesurfaces (ninth and tenth surfaces) 209 d and 210 d which extend in thedirection of the first wiring 200 d and are adjacent to the back surface201 d. In the first wiring 200 d, an angle between the back surface 201d and one side surface 209 d and an angle between the back surface 201 dand the other side surface 210 d are acute angles. In the first wiring200 d, the angle between the back surface 201 d and the one side surface209 d is the same as the angle between the back surface 201 d and theother side surface 210 d. The one side surface 209 d of the first wiring200 d according to the present modification is recessed inward (towardthe positive side in the D3 direction). The one side surface 209 dincludes an upper side surface (eleventh surface) 211 d adjacent to thefront surface 202 d. The other side surface 210 d of the first wiring200 d is recessed inward (toward the negative side in the D3 direction).The other side surface 210 d includes an upper side surface (twelfthsurface) 212 d adjacent to the front surface 202 d. In FIG. 6(A), anangle between the front surface 202 d and the upper side surface 211 dand an angle between the front surface 202 d and the upper side surface212 d are approximately 90°. However, the configuration is not limitedthereto, and the angle between the front surface 202 d and the upperside surface 211 d may be smaller than an external angle of the anglebetween the back surface 201 d and the one side surface 209 d. The anglebetween the front surface 202 d and the upper side surface 211 d ispreferably in a range of 60° or more and 90° or less. It is sufficientfor the angle between the front surface 202 d and the upper side surface212 d to be smaller than the external angle of the angle between theback surface 201 d and the other side surface 210 d. The angle betweenthe front surface 202 d and the upper side surface 212 d is preferablyin a range of 60° or more and 90° or less. That is, the one side surface209 d of the first wiring 200 d includes a shape (the upper side surface211 d) that is connected to the front surface 202 d at an angle smallerthan the external angle of the angle between the back surface 201 d andthe one side surface 209 d. The other side surface 210 d of the firstwiring 200 d includes a shape (the upper side surface 212 d) that isconnected to the front surface 202 d at an angle smaller than theexternal angle of the angle between the back surface 201 d and the otherside surface 210 d. However, the configuration is not limited thereto,and the one side surface 209 d and the other side surface 210 d mayfurther include different surfaces, and the respective surfaces formingthe one side surface 209 d and the other side surface 210 d may form acorner (intersection line) or may be continuously connected by a curvedsurface. The first wiring 200 d according to the present modificationfurther includes a protrusion d that extends in a direction orthogonalto the direction of the first wiring 200 d and protrudes in a surfacedirection of the front surface between the front surface 202 d and anadjacent surface. That is, the first wiring 200 d has the protrusions dprotruding in the D3 direction between the front surface 202 d and theupper side surface 211 d and between the front surface 202 d and theupper side surface 212 d. That is, in a cross section that intersectsperpendicularly with a direction in which the first wiring 200 dextends, the first wiring 200 d is line-symmetric about the extendingdirection (the D2 direction). Since the angle between the front surface202 d and the upper side surface 211 d is smaller than the externalangle of the angle between the back surface 201 d and the one sidesurface 209 d, and the angle between the front surface 202 d and theupper side surface 212 d is smaller than the external angle of the anglebetween the back surface 201 d and the other side surface 210 d in thefirst wiring 200 d, it is possible to suppress the visibility of theupper side surface 211 d and the upper side surface 212 d of the firstwiring 200 d in a plan view in the D1 direction. Furthermore, a wiringresistance can be suppressed by increasing a cross-sectional area of thefirst wiring 200 d that intersects perpendicularly with the direction inwhich the wiring extends. Thus, the transparency, the reliability, andthe conductivity of the wiring board 10 d can be improved.

As illustrated in FIG. 6(B), the second wiring 300 d has a pair of sidesurfaces (fifth and sixth surfaces) 305 d and 306 d which extend in thedirection of the second wiring 300 d and are adjacent to the backsurface 303 d. In the second wiring 300 d, an angle between the backsurface 303 d and one side surface 305 d and an angle between the backsurface 303 d and the other side surface 306 d are acute angles. In thesecond wiring 300 d, the angle between the back surface 303 d and theother side surface 306 d is smaller than the angle between the backsurface 303 d and the one side surface 305 d. The one side surface 305 dof the second wiring 300 d according to the present modification isrecessed inward (toward the negative side in the D2 direction). The oneside surface 305 d includes an upper side surface (seventh surface) 307d adjacent to the front surface 304 d. The other side surface 306 d ofthe second wiring 300 d is recessed inward (toward the positive side inthe D2 direction). The other side surface 306 d includes an upper sidesurface (eighth surface) 308 d adjacent to the front surface 304 d. InFIG. 6(B), an angle between the front surface 304 d and the upper sidesurface 307 d and an angle between the front surface 304 d and the upperside surface 308 d are approximately 90°. However, the configuration isnot limited thereto, and the angle between the front surface 304 d andthe upper side surface 307 d may be smaller than an external angle ofthe angle between the back surface 303 d and the one side surface 305 d.The angle between the front surface 304 d and the upper side surface 307d is preferably in a range of 60° or more and 90° or less. It issufficient for the angle between the front surface 304 d and the upperside surface 308 d to be smaller than the external angle between theback surface 303 d and the other side surface 306 d. The angle betweenthe front surface 304 d and the upper side surface 308 d is preferablyin a range of 60° or more and 90° or less. That is, the one side surface305 d of the second wiring 300 d includes a shape (the upper sidesurface 307 d) that is connected to the front surface 304 d at an anglesmaller than the external angle of the angle between the back surface303 d and the one side surface 305 d. The other side surface 306 d ofthe second wiring 300 d includes a shape (the upper side surface 308 d)that is connected to the front surface 304 d at an angle smaller thanthe external angle of the angle between the back surface 303 d and theother side surface 306 d. However, the configuration is not limitedthereto, and the one side surface 305 d and the other side surface 306 dmay further include different surfaces, and the respective surfacesforming the one side surface 305 d and the other side surface 306 d mayform a corner (intersection line) or may be continuously connected by acurved surface. The second wiring 300 d according to the presentmodification further includes the protrusion d that extends in adirection orthogonal to the direction of the second wiring 300 d andprotrudes in a surface direction of the front surface between the frontsurface 304 d and an adjacent surface. That is, the second wiring 300 dhas the protrusions d protruding in the D2 direction between the frontsurface 304 d and the upper side surface 307 d and between the frontsurface 202 d and the upper side surface 308 d. In a cross section thatintersects perpendicularly with a direction in which the second wiring300 d extends, the second wiring 300 d is asymmetric about the extendingdirection (the D3 direction). With the arrangement in which the anglebetween the back surface 303 d and the other side surface 306 d issmaller than the angle between the back surface 303 d and the one sidesurface 305 d in the second wiring 300 d, the line width of the backside 303 d becomes large, and it is possible to improve the adhesionbetween the substrate 100 d and the second wiring 300 d whilesuppressing the visibility of the one side surface 305 d of the secondwiring 300 d in a plan view in the D1 direction. Since the angle betweenthe front surface 304 d and the upper side surface 307 d is smaller thanthe external angle of the angle between the back surface 303 d and theone side surface 305 d, and the angle between the front surface 304 dand the upper side surface 308 d is smaller than the external angle ofthe angle between the back surface 303 d and the other side surface 306d in the second wiring 300 d, it is possible to suppress the visibilityof the upper side surface 307 d and the upper side surface 308 d of thesecond wiring 300 d in a plan view in the D1 direction. Furthermore, awiring resistance can be suppressed by increasing a cross-sectional areaof the second wiring 300 d that intersects perpendicularly with thedirection in which the wiring extends. Thus, the transparency, thereliability, and the conductivity of the wiring board 10 d can beimproved.

As described above, the wiring board 10 d according to the presentmodification is arranged such that the line width of the front surface304 d of the second wiring 300 d of the substrate 100 d is smaller thanthe line width of the front surface 202 d of the first wiring 200 d, andthus, it is possible to suppress the visibility of the second wiring 300d in a plan view in the D1 direction while maintaining the reliabilityof the first wiring 200 d having the radio wave transmission/receptionfunction. Since the first wiring 200 d and the second wiring 300 d arearranged such that the line width of the surface in contact with thesubstrate 100 d is larger than the surface facing the side opposite tothe surface in contact with the substrate 100 d, the adhesion betweenthe substrate 100 d and each of the first wiring 200 d and the secondwiring 300 d can be improved while suppressing the visibility of thefirst wiring 200 d and the second wiring 300 d in a plan view in the D1direction. Since the angle between the front surface 202 d and the upperside surface 211 d is smaller than the external angle of the anglebetween the back surface 201 d and the one side surface 209 d, and theangle between the front surface 202 d and the upper side surface 212 dis smaller than the external angle of the angle between the back surface201 d and the other side surface 210 d in the first wiring 200 d, it ispossible to suppress the visibility of the upper side surface 211 d andthe upper side surface 212 d of the first wiring 200 d in a plan view inthe D1 direction. With the arrangement in which the angle between theback surface 303 d and the other side surface 306 d is smaller than theangle between the back surface 303 d and the one side surface 305 d inthe second wiring 300 d, it is possible to improve the adhesion betweenthe substrate 100 d and the second wiring 300 d while suppressing thevisibility of the one side surface 305 d of the second wiring 300 d in aplan view in the D1 direction. Since the angle between the front surface304 d and the upper side surface 307 d is smaller than the externalangle of the angle between the back surface 303 d and the one sidesurface 305 d, and the angle between the front surface 304 d and theupper side surface 308 d is smaller than the external angle of the anglebetween the back surface 303 d and the other side surface 306 d in thesecond wiring 300 d, it is possible to suppress the visibility of theupper side surface 307 d and the upper side surface 308 d of the secondwiring 300 d in a plan view in the D1 direction. Furthermore, a wiringresistance can be suppressed by increasing each cross-sectional area ofthe first wiring 200 d and the second wiring 300 d that intersectsperpendicularly with the direction in which each wiring extends. Thus,the transparency, the reliability, and the conductivity of the wiringboard 10 d can be improved.

The wiring board 10 d according to the present modification can bemounted on a display device as a wireless communication module by beingconnected to a wireless communication circuit. The wiring board 10 d isarranged on an upper surface of a display region such that the substrate100 d faces the display region of the display device so that it ispossible to suppress the visibility of the first wiring 200 d and thesecond wiring 300 d in a plan view in the D1 direction. The wiring board10 d is arranged such that a direction of the first wiring 200 is avertical direction of the display region and the upper side surface 307d of the second wiring 300 d is in the upper direction of the displayregion (light incident direction) so that the reflection of light by theother side surface 306 d of the second wiring 300 d can be suppressed.When the wiring board 10 d is arranged on an upper surface of thedisplay region, a protective film is arranged so as to cover the uppersurface of the substrate 100 d. Since the first wiring 200 d and thesecond wiring 300 d have the protrusions d, the adhesion between each ofthe first wiring 200 d and the second wiring 300 d and the protectivefilm can be improved. Thus, it is possible to provide the display deviceincluding the wiring board having the radio wave transmission/receptionfunction with improved transparency, reliability, and conductivity.

<Fifth Modification>

A wiring board 10 e according to the present modification includes asubstrate 100 e, a first wiring 200 e, and a second wiring 300 e, whichis similar to the wiring board 10 according to the embodimentillustrated in FIGS. 1 and 2. The wiring board 10 e according to thepresent modification includes a curved surface (curved portion) e at anintersection between the first wiring 200 e and the second wiring 300 e.

A configuration of the wiring board 10 e according to the presentmodification will be described with reference to FIGS. 7 and 8. Here,the configuration of the wiring board 10 e according to the presentmodification is the same as the configuration of the wiring board 10illustrated in FIGS. 1 and 2 except for the curved surface e at theintersection between the first wiring 200 e and the second wiring 300 e.Thus, detailed descriptions of the same portions as those in the modeillustrated in FIGS. 1 and 2 will be omitted.

[Configuration of Wiring Board]

FIG. 7 is a top view illustrating an example of the wiring boardaccording to the present modification. FIG. 7 is an enlarged top view ina region C of FIG. 1. FIG. 8 is a cross-sectional view illustrating anexample of the wiring board according to the present modification. FIG.8(A) is an enlarged cross-sectional view taken along a chain line D-D′of FIG. 7. FIG. 8(B) is an enlarged cross-sectional view taken along achain line E-E′ of FIG. 7.

As illustrated in FIG. 7, the wiring board 10 e includes the substrate100 e, the first wiring 200 e, and the second wiring 300 e. In thepresent modification, the first wiring 200 e is orthogonal to the secondwiring 300 e. However, it is sufficient for planar shapes of the firstwiring 200 e and the second wiring 300 e to intersect or to be connectedwithout being limited thereto. As illustrated in FIGS. 7 and 8, an uppersurface of the substrate 100 e, side surfaces adjacent to a back surface(first surface) 201 e of the first wiring 200 e, and side surfacesadjacent to a back surface (third surface) 303 e of the second wiring300 e form four corners in a plan view. In the present modification, acorner formed by the upper surface of the substrate 100 e, the otherside surface (tenth surface) 210 e of the first wiring 200 e, and theother side surface (sixth surface) 306 e of the second wiring 300 eincludes a curved surface e that is continuous with these surfaces. Thatis, the curved surface e continuously connects the other side surface210 e of the first wiring 200 e and the other side surface 306 e of thesecond wiring 300 e. The curved surface e has a shape curved inward inboth of a cross section perpendicular to a direction of the first wiring200 e and a cross section perpendicular to a direction of the secondwiring 300 e. However, the configuration is not limited thereto, and itis sufficient for the curved surface e to be arranged at one or more offour corners in a plan view formed by the upper surface of the substrate100 e, the side surfaces adjacent to the back surface 201 e of the firstwiring 200 e, and the side surfaces adjacent to the back surface 303 eof the second wiring 300 e. That is, the first wiring 200 e isasymmetric about a longitudinal direction (D2 direction) in the crosssection that intersects perpendicularly with the direction of the firstwiring 200 e at the corner including the curved surface e. The secondwiring 300 e is asymmetric about a longitudinal direction (D3 direction)in the cross section that intersects perpendicularly with the directionof the second wiring 300 e at the corner including the curved surface e.A radius of curvature of the curved surface e is preferably 20% or moreof a height of the second wiring 300 e in the cross sectionperpendicular to the direction of the second wiring 300 e.

Since the curved surface e is provided at the corner formed by the uppersurface of the substrate 100 e, the side surface adjacent to the backsurface 201 e of the first wiring 200 e, and the side surface adjacentto the back surface 303 e of the second wiring 300 e, line widths of theback surface 201 e and the back surface 303 e become large, and it ispossible to improve the adhesion between the substrate 100 e and thefirst wiring 200 e and between the substrate 100 e and the second wiring300 e. Furthermore, since each cross-sectional area of the first wiring200 e and the second wiring 300 e that intersects perpendicularly withthe direction in which each wiring extends increases, it is possible tosuppress a wiring resistance while suppressing the visibility of a frontsurface (second surface) 202 e of the first wiring 200 e and a frontsurface (fourth surface) 304 e of the second wiring 300 e in a plan viewin the D1 direction. Thus, the transparency, the reliability, and theconductivity of the wiring board 10 e can be improved.

The wiring board 10 e according to the present modification can bemounted on a display device as a wireless communication module by beingconnected to a wireless communication circuit. The wiring board 10 e isarranged on an upper surface of a display region such that the substrate100 e faces the display region of the display device so that it ispossible to suppress the visibility of the first wiring 200 e and thesecond wiring 300 e in a plan view in the D1 direction. Since the wiringboard 10 e is arranged such that a direction of the first wiring 200 eis a vertical direction of the display region and the curved surface eis in the lower direction of the display region, it is possible tosuppress reflection of light by the curved surface e. Thus, it ispossible to provide the display device including the wiring board havingthe radio wave transmission/reception function with improvedtransparency, reliability, and conductivity.

<Sixth Modification>

A wiring board 10 f according to the present modification includes asubstrate 100 f, a first wiring 200 f, and a second wiring 300 f, whichis similar to the wiring board 10 a (FIG. 3) according to the firstmodification. The wiring board 10 f according to the presentmodification includes a curved surface f at an intersection between thefirst wiring 200 f and the second wiring 300 f.

A configuration of the wiring board 10 f according to the presentmodification will be described with reference to FIGS. 9 and 10. Here,the configuration of the wiring board 10 f according to the presentmodification is the same as the configuration of the wiring board 10 aaccording to the first modification illustrated in FIG. 3 except for thecurved surface f at the intersection between the first wiring 200 f andthe second wiring 300 f. Thus, detailed descriptions of the sameportions as those in the first modification will be omitted.

[Configuration of Wiring Board]

FIG. 9 is a top view illustrating an example of the wiring boardaccording to the present modification. FIG. 9 is an enlarged top view inthe region C of FIG. 1. FIG. 10 is a cross-sectional view illustratingan example of the wiring board according to the present modification.FIG. 10(A) is an enlarged cross-sectional view taken along a chain lineD-D′ of FIG. 9. FIG. 10(B) is an enlarged cross-sectional view takenalong a chain line E-E′ of FIG. 9.

As illustrated in FIG. 9, the wiring board 10 f includes the substrate100 f, the first wiring 200 f, and the second wiring 300 f. In thepresent modification, the first wiring 200 f is orthogonal to the secondwiring 300 f. However, it is sufficient for planar shapes of the firstwiring 200 f and the second wiring 300 f to intersect or to be connectedwithout being limited thereto. As illustrated in FIGS. 9 and 10, anupper surface of the substrate 100 f, side surfaces adjacent to a backsurface (first surface) 201 f of the first wiring 200 f, and sidesurfaces adjacent to a back surface (third surface) 303 f of the secondwiring 300 f form four corners in a plan view. In the presentmodification, a corner formed by the upper surface of the substrate 100f, one side surface (ninth surface) 209 f of the first wiring 200 f, andthe other side surface (sixth surface) 306 f of the second wiring 300 fincludes a curved surface f that is continuous with these surfaces. Thatis, the curved surface f continuously connects the one side surface 209f of the first wiring 200 f and the other side surface 306 f of thesecond wiring 300 f. Furthermore, a corner formed by the upper surfaceof the substrate 100 f, the other side surface (tenth surface) 210 f ofthe first wiring 200 f, and the other side surface 306 f of the secondwiring 300 f includes the curved surface f that is continuous with thesesurfaces. That is, the curved surface f continuously connects the otherside surface 210 f of the first wiring 200 f and the other side surface306 f of the second wiring 300 f. However, the configuration is notlimited thereto, and it is sufficient for the curved surface f to bearranged at one or more of four corners in a plan view formed by theupper surface of the substrate 100 f, the side surfaces adjacent to theback surface 201 f of the first wiring 200 f, and the side surfacesadjacent to the back surface 303 f of the second wiring 300 f. Thecurved surface f is preferably arranged at one or more of two cornersformed by the upper surface of the substrate 100 f, the side surfaceadjacent to the back surface 201 f of the first wiring 200 f, and theother side surface 306 f of the second wiring 300 f. That is, the firstwiring 200 f is line-symmetric about a longitudinal direction (D2direction) in the cross section that intersects perpendicularly with thedirection of the first wiring 200 f at the corner including the curvedsurface f. That is, the second wiring 300 f is asymmetric about alongitudinal direction (D3 direction) in the cross section thatintersects perpendicularly with the direction of the second wiring 300 fat the corner including the curved surface f. A radius of curvature ofthe curved surface f is preferably 20% or more of a height of the secondwiring 300 e in the cross section perpendicular to the direction of thesecond wiring 300 e.

Since the curved surface f is provided at the corner formed by the uppersurface of the substrate 100 f, the side surface adjacent to the backsurface 201 f of the first wiring 200 f, and the other side surface 306f of the second wiring 300 f, line widths of the back surface 201 f andthe back surface 303 f become large, and it is possible to improve theadhesion between the substrate 100 f and the first wiring 200 f andbetween the substrate 100 f and the second wiring 300 f. Furthermore,since each cross-sectional area of the first wiring 200 f and the secondwiring 300 f that intersects perpendicularly with the direction in whicheach wiring extends increases, it is possible to suppress a wiringresistance while suppressing the visibility of a front surface (secondsurface) 202 f of the first wiring 200 f and a front surface (fourthsurface) 304 f of the second wiring 300 f in a plan view in the D1direction. Thus, the transparency, the reliability, and the conductivityof the wiring board 10 f can be improved.

The wiring board 10 f according to the present modification can bemounted on a display device as a wireless communication module by beingconnected to a wireless communication circuit. The wiring board 10 f isarranged on an upper surface of a display region such that the substrate100 f faces the display region of the display device so that it ispossible to suppress the visibility of the first wiring 200 f and thesecond wiring 300 f in a plan view in the D1 direction. Since the wiringboard 10 f is arranged such that a direction of the first wiring 200 fis a vertical direction of the display region and the curved surface fis in the lower direction of the display region, it is possible tosuppress reflection of light by the curved surface f. Thus, it ispossible to provide the display device including the wiring board havingthe radio wave transmission/reception function with improvedtransparency, reliability, and conductivity.

[Method for Manufacturing Wiring Board 10]

A method for manufacturing the wiring boards according to the presentembodiment and the respective modifications will be described withreference to FIGS. 11 and 12. In FIGS. 11 and 12, the same elements asthe elements described in the above-described embodiment and therespective modifications are denoted by the same reference signs. Here,detailed descriptions of the same portions as those in the modesillustrated in FIGS. 1 to 10 will be omitted.

FIG. 11(A) is a view illustrating a step of forming a conductive layer400 on the upper surface of the substrate 100 in the method formanufacturing the wiring board according to the present embodiment. Asillustrated in FIG. 11(A), the conductive layer 400 is formed oversubstantially the entire surface of the substrate 100. In the presentembodiment, a thickness of the conductive layer 400 is 200 nm. However,the thickness of the conductive layer 400 can be appropriately selectedin a range of 10 nm or more and 1000 nm or less without being limitedthereto. In the present embodiment, the conductive layer 400 is formedby a sputtering method using copper. As a method for forming theconductive layer 400, a plasma CVD method can be also used.

FIG. 11(B) is a view illustrating a step of forming an insulating layer500 on the upper surface of the substrate 100 in the method formanufacturing the wiring board according to the present embodiment. Asillustrated in FIG. 11(B), the insulating layer 500 is formed oversubstantially the entire surface of the substrate 100. A thickness ofthe insulating layer 500 is 1200 nm. However, the thickness of theinsulating layer 500 can be appropriately selected in a range of 500 nmor more and 2500 nm or less without being limited thereto. Theinsulating layer 500 may be a material having an electrical insulatingproperty.

FIG. 11(C) is a view illustrating a step of forming a first trench 510in which the first wiring 200 is arranged and a second trench 520 (notillustrated) in which the second wiring 300 is arranged on an uppersurface of the insulating layer 500 in the method for manufacturing thewiring board according to the present embodiment. As illustrated in FIG.11(C), the first trench 510 and the second trench 520 are formed by animprinting method in the present embodiment. The insulating layer 500 issoftened, and a mold 600 having protruding portions corresponding to thefirst trench 510 and the second trench 520 is press-fitted thereto. Inthis state, the insulating layer 500 is cured and the mold 600 isseparated from the insulating layer 500, whereby the insulating layer500 having a cross-sectional structure illustrated in FIG. 11(D) can beobtained.

The first trench 510 corresponds to the first wiring 200, and the secondtrench 520 corresponds to the second wiring 300. Therefore, the firsttrench 510 extending in the first direction is orthogonal to the secondtrench 520 extending in the second direction. Further, the first trench510 is longer than the second trench 520, and an opening width of thefirst trench 510 is formed to be larger than an opening width of thesecond trench 520. Here, the opening width means a width of an openingportion parallel to the upper surface of the substrate 100 in a crosssection that intersects perpendicularly with a direction in which eachtrench extends. Each aspect ratio of the first trench 510 and the secondtrench 520 can be appropriately selected according to the application.Here, the aspect ratio of each of the first trench 510 and the secondtrench 520 is defined as a depth with respect to the opening portionwidth. If the aspect ratio of each of the first trench 510 and thesecond trench 520 is too small, it becomes difficult to form a finepattern of the first wiring 200 and the second wiring 300 on the wiringboard 10. When the aspect ratio of each of the first trench 510 and thesecond trench 520 is too large, it becomes difficult to fill the firsttrench 510 and the second trench 520 with a conductor. Note that theopening width of the first trench 510 may be the same as the openingwidth of the second trench 520.

When forming the first trench 510 and the second trench 520 by theimprinting method, a direction in which the mold 600 is separated fromthe insulating layer 500 is preferably a direction in which the longerfirst wiring 200 (first trench 510) extends. The direction in which themold 600 is separated from the insulating layer 500 is more preferably adirection from one side surface 305 to the other side surface 306 of thesecond wiring 300. That is, the direction in which the mold 600 isseparated from the insulating layer 500 is more preferably from thefirst side 102 to the second side 104 of the substrate 100 (thedirection of the first wiring 200, the first direction, and the oppositedirection of D2). When the insulating layer 500 is formed in thismanner, the cross-sectional shapes of the first wiring 200 and thesecond wiring 300 according to the above-described embodiment and therespective modifications can be formed. However, the method is notlimited thereto, and the insulating layer 500 may be formed by aphotolithography method in the method for manufacturing the wiring board10 according to the above-described embodiment and the respectivemodifications. In this case, a resist pattern is formed by thephotolithography method so as to expose the conductive layer 400 in aregion where the first wiring 200 and the second wiring 300 are formed.

As illustrated in FIG. 11(D), there is a case where a residue of aninsulating material remain at each bottom of the first trench 510 andthe second trench 520 formed in the insulating layer 500. Thus, theresidue of the insulating material is removed by performing a wettreatment using a permanganate solution or N-methyl-2-pyrrolidone or adry treatment using oxygen plasma. As the residue of the insulatingmaterial is removed, the first trench 510 and the second trench 520exposing the conductive layer 400 can be formed as illustrated in FIG.12(A).

FIG. 12(B) is a view illustrating a step of forming a first conductor410 corresponding to the first wiring 200 and a second conductor 420(not illustrated) corresponding to the second wiring 300 in the methodfor manufacturing the wiring board according to the present embodiment.The first trench 510 and the second trench 520 of the insulating layer500 formed in FIG. 12(A) are filled with the first conductor 410 and thesecond conductor 420. In the present embodiment, the first trench 510and the second trench 520 of the insulating layer 500 are filled withcopper by an electrolytic plating method using the conductive layer 400as a seed layer. Furthermore, the first conductor 410 and the secondconductor 420 are formed so as to protrude from the upper surface of theinsulating layer 500 (on the opposite side of the substrate 100). Thefirst conductor 410 and the second conductor 420 are formed on the uppersurface of the insulating layer 500 to be larger than the opening widthof the first trench 510 and the opening width of the second trench 520.In the present embodiment, each protruding portion of the firstconductor 410 and the second conductor 420 is formed in a semicircularshape in a cross-sectional view, and each cross-sectional shape of thefirst conductor 410 and the second conductor 420 is formed in a mushroomshape. However, the configuration is not limited thereto, and it issufficient for the first conductor 410 and the second conductor 420 toprotrude in a surface direction of the insulating layer 500 more thanthe opening width and protrude in a stacking direction on the uppersurface of the insulating layer 500. For example, each protrudingportion of the first conductor 410 and the second conductor 420 may beformed in a rectangular parallelepiped, and each cross-sectional shapeof the first conductor 410 and the second conductor 420 may be formed ina T shape. Each height of the first conductor 410 and the secondconductor 420 on the upper surface of the insulating layer 500 in thestacking direction (D1 direction) is preferably 5% or more and 80% orless of a height of the first trench 510 in the stacking direction (D1direction) of the second trench 520.

FIG. 12(C) is a view illustrating a step of removing the insulatinglayer 500 in the method for manufacturing the wiring board according tothe present embodiment. As illustrated in FIG. 12(C), the wet treatmentusing a permanganate solution or N-methyl-2-pyrrolidone or the drytreatment using oxygen plasma is performed to remove the insulatinglayer 500 on the substrate 100.

FIG. 12(D) is a view illustrating a step of removing the conductivelayer 400 in the method for manufacturing the wiring board according tothe present embodiment. As illustrated in FIG. 12(D), the conductivelayer 400 is etched so as to expose the upper surface of the substrate100 by performing a wet treatment using a hydrogen peroxide solution. Atthis time, the first conductor 410 and the second conductor 420 are alsomolded by etching. As the first conductor 410 and the second conductor420 are molded in this manner, the cross-sectional shapes of the firstwiring 200 and the second wiring 300 according to the above-describedembodiment and the respective modifications can be formed.

Although not illustrated in the drawing, it is preferable that the firstwiring 200 and the second wiring 300 be subjected to a blackeningtreatment on surfaces other than the surface in contact with thesubstrate 100. In the present embodiment, the front surface (secondsurface) 202 of the first wiring 200, and the front surface (fourthsurface) 304 of the second wiring 300 are subjected to a blackeningtreatment by forming copper oxide which is an oxide film of each wiringmaterial. Since the front surfaces of the first wiring 200 and thesecond wiring 300 are subjected to the blackening treatment, it ispossible to suppress light reflection of the first wiring 200 and thesecond wiring 300, and to achieve absorption of external light of thewiring board 10 and contrast improvement.

As described above, with the method for manufacturing the wiring board10 according to the present embodiment, the cross-sectional shapes ofthe first wiring 200 and the second wiring 300 according to theabove-described embodiment and the respective modifications can beformed by the simple method of forming the conductor to be thicker thanthe insulating layer in the stacking direction and performing molding bywet etching. Thus, it is possible to manufacture the wiring board 10with the improved transparency, reliability, and conductivity.

Next, a modification of the method for manufacturing the wiring boardwill be described with reference to FIGS. 13(A) to 13(D). FIGS. 13(A) to13(D) are views illustrating the modification of the method formanufacturing the wiring board, and are views corresponding to FIGS.12(A) to 12(D).

First, the first trench 510 and the second trench 520 exposing theconductive layer 400 are formed in the same manner as the stepsillustrated in FIGS. 11(A) to 11(D) (FIG. 13(A)).

Next, the first conductor 410 corresponding to the first wiring 200 andthe second conductor 420 (not illustrated) corresponding to the secondwiring 300 are formed as illustrated in FIG. 13(B). That is, the firsttrench 510 and the second trench 520 of the insulating layer 500 arefilled with copper by an electrolytic plating method using theconductive layer 400 as a seed layer. In this case, the first conductor410 and the second conductor 420 are formed to be lower than the uppersurface of the insulating layer 500 (on the opposite side of thesubstrate 100). At this time, each upper surface of the first conductor410 and the second conductor 420 is formed in a semicircular shape in across-sectional view.

Subsequently, for example, a wet treatment using a permanganate solutionor N-methyl-2-pyrrolidone or a dry treatment using oxygen plasma isperformed to remove the insulating layer 500 on the substrate 100 asillustrated in FIG. 13(C).

Thereafter, the conductive layer 400 is etched so as to expose the uppersurface of the substrate 100, for example, by performing a wet treatmentusing a hydrogen peroxide solution as illustrated in FIG. 13(D). At thistime, the first conductor 410 and the second conductor 420 are alsomolded by etching. Specifically, shapes of the first conductor 410 andthe second conductor 420 (a shape of the side surface, a shape of thecurved surface, and the like) can be adjusted by appropriately settingetching conditions (a type of an etching solution, a concentration, andan etching time) and the like. In this manner, the cross-sectionalshapes of the first wiring 200 and the second wiring 300 according tothe above-described embodiment and the respective modifications can beformed.

Next, a description will be given regarding an example of a wirelesscommunication module in which a wireless communication circuit isconnected to the wiring boards according to the above-describedembodiment and the respective modifications. A configuration of awireless communication module 20A according to the present embodimentwill be described with reference to FIG. 14. Here, detailed descriptionsof the same portions as those in the modes illustrated in FIGS. 1 to 13will be omitted.

[Configuration of Wireless Communication Module]

FIG. 14 is a top view illustrating an example of the wirelesscommunication module according to the present embodiment. As illustratedin FIG. 14, the wireless communication module 20A includes a wiringboard 10 g and a circuit 700 g. The circuit 700 g is a wirelesscommunication circuit, and is connected to a plurality of first wirings200 g of the wiring board 10 g.

The wiring board 10 g includes a substrate 100 g, the first wirings 200g, and second wirings 300 g. The first wiring 200 g and the secondwiring 300 g are arranged on an upper surface of the substrate 100 g. Inthe present embodiment, four first wirings 200 g and four second wirings300 g are arranged, but the configuration is not limited thereto. It issufficient that two or more first wirings 200 g and one or more secondwirings 300 g are provided.

As illustrated in FIG. 14, a line-and-space shape in which a pluralityof lines extend independently from a first side 102 of the substrate 100g toward a second side 104 opposite to the first side 102 (in alongitudinal direction of the first wiring 200 g, a first direction, andan opposite direction of D2) is illustrated as a planar shape of thefirst wiring 200 g as viewed in a D1 direction. A line-and-space shapein which a plurality of lines extend independently in a directionorthogonal to the direction of the first wiring 200 g (a longitudinaldirection of the second wiring 300 g, a second direction, and a D3direction) is illustrated as a planar shape of the second wiring 300 gas viewed in a D1 direction. That is, a regular grid or mesh shape isformed by the first wiring 200 g extending in the first direction andthe second wiring 300 g extending in the second direction. The pluralityof first wirings 200 g are orthogonal to the plurality of second wirings300 g. The first wiring 200 g is longer than the second wiring 300 g.Further, an interval between the plurality of second wirings 300 g islarger than an interval between the plurality of first wirings 200 g.However, it is sufficient that a plurality of lines intersect or areconnected with each other in the planar shape of the first wiring 200 gand the second wiring 300 g without being limited to such a shape. Forexample, a direction of the first wiring 200 g and a direction of thesecond wiring 300 g may intersect at an acute angle or may intersect atan obtuse angle. Further, the repetitive shape is not necessarilyuniform on the substrate 100 g. Here, when a region where the pluralityof first wirings 200 g and the plurality of second wirings 300 g are notarranged is set as an opening of the wiring board 10 g on the uppersurface of the substrate 100 g, an aperture ratio (visible lighttransmissivity) is preferably 80% or more. If the aperture ratio is lessthan 80%, the transmittance of the wiring board 10 g deteriorates Withthe arrangement in which the interval between the plurality of secondwirings 300 g is larger than the interval between the plurality of firstwirings 200 g, it is possible to suppress the visibility of the sparesecond wiring 300 g corresponding to the disconnection of the firstwiring 200 g or the like while maintaining a conductivity of the firstwiring 200 g having a radio wave transmission/reception function. Thus,a conductivity and transparency of the wiring board 10 g can beimproved.

FIG. 15 is a top view illustrating an example of a wirelesscommunication module according to a modification. As illustrated in FIG.15, the wireless communication module 20A is, for example, a module forNFC (Near Field Communication), and includes the wiring board 10 g andthe circuit 700 g. In this case, the wiring board 10 g has a wiringregion 106 g formed in a spiral shape as a whole in a plan view. Thewiring region 106 g includes the plurality of first wirings 200 g andthe plurality of second wirings 300 g. That is, the first wiring 200 gand the second wiring 300 g are formed in a mesh shape or a grid shapeinside the wiring region 106 g. In this case, the transparency of thewiring board 10 g is enhanced, and thus, for example, the wiring board10 g for NFC can be also arranged on a display screen.

Note that the present disclosure is not limited to the above-describedembodiments, and can be appropriately changed within a scope notdeparting from a gist. The respective embodiments described above asembodiments of the present disclosure can be implemented appropriatelyin combinations as long as there is no confliction with each other.Further, one that is obtained by addition, deletion, or a design changeof a component appropriately performed based on the wiring board of eachof the embodiments by a person skilled in the art or one that isobtained by adding or omitting a step or changing a condition is alsoincluded in the scope of the present invention as long as having thegist of the present invention.

Even operations and effects that are different from those brought by themodes of each of the above-described embodiments but are evident fromthe description of the specification or can be easily predicted by aperson skilled in the art are construed as those naturally brought bythe present invention.

EXAMPLES

Structures of the first wiring 200 and the second wiring 300 included inthe wiring board according to the embodiment of the present disclosuredescribed above will be described in more detail.

Reference Example 1

Parameters of the first wiring 200 and the second wiring 300 in a wiringboard according to Reference Example 1 are given as follows.

Width of the first wiring 200: 1 μm

Height of the first wiring 200: 1 μm

Interval between the first wirings 200: 20 μm

Width of second wiring 300: 2 μm

Height of second wiring 300: 1 μm

Interval between the second wirings 300: 20 μm

The wiring board according to Reference Example 1 of the presentdisclosure is the same as the wiring board according to the sixthmodification (FIGS. 9 and 10) except for the width and interval (pitch)of each wiring, and thus, a detailed description thereof will beomitted. Manufacturing steps of the wiring board are the same as thoseof the mode illustrated in FIGS. 11 to 13, and thus a description willbe omitted.

An intersection between the first wiring 200 and the second wiring 300was observed with an electron microscope (SEM) using the wiring board ofReference Example 1. FIG. 16 illustrates an image of an upper surface ofthe wiring board of Reference Example 1 observed using the electronmicroscope (SEM). FIG. 17 illustrates an image of the intersectionbetween the first wiring 200 and the second wiring 300 in ReferenceExample 1 observed using the electron microscope (SEM).

FIG. 17 is the electron microscope image of the intersection between thefirst wiring 200 and the second wiring 300 in Reference Example 1. Asillustrated in FIGS. 17(A) and 17(B), the wiring board 10 according tothe reference example 1 includes two curved surfaces at the intersectionbetween the first wiring 200 and the second wiring 300. It has beenobserved that the corner formed by the upper surface of the substrate100, the one side surface 209 of the first wiring 200, and the otherside surface 306 of the second wiring 300 includes the curved surface fthat is continuous with these surfaces. Furthermore, it has beenobserved that the corner formed by the upper surface of the substrate100, the other side surface 210 of the first wiring 200, and the otherside surface 306 of the second wiring 300 includes the curved surface fthat is continuous with these surfaces.

Second Embodiment

Next, a second embodiment will be described with reference to FIGS. 18to 37. FIGS. 18 to 37 are views illustrating the second embodiment.

In the present embodiment, an “X direction” is a direction perpendicularto a longitudinal direction of the antenna pattern region, and is adirection perpendicular to a direction of a length corresponding to afrequency band of an antenna wiring. A “Y direction” is a directionperpendicular to the X direction and parallel to the longitudinaldirection of the antenna pattern region, and is a direction parallel tothe direction of the length corresponding to the frequency band of theantenna wiring. A “Z direction” is a direction perpendicular to both theX direction and the Y direction and parallel to a thickness direction ofa wiring board. Further, a “front surface” refers to a surface on thepositive side in the Z direction, and is a surface on which the antennawiring is provided on the substrate. A “back surface” refers to asurface on the negative side in the Z direction, and is a surface on theopposite side of the surface on which the antenna wiring is provided onthe substrate. Note that a description is given by exemplifying a casewhere the wiring pattern region 20 is the antenna pattern region 20having a radio wave transmission/reception function (function as anantenna) in the present embodiment, but the wiring pattern region 20does not necessarily have the radio wave transmission/reception function(function as the antenna).

[Configuration of Wiring Board]

A configuration of the wiring board according to the present embodimentwill be described with reference to FIGS. 18 to 22. FIGS. 18 to 22 areviews illustrating the wiring board according to the present embodiment.

As illustrated in FIG. 18, the wiring board 10 according to the presentembodiment is arranged, for example, on a display of an image displaydevice. Such a wiring board 10 includes: a substrate 11 havingtransparency, an antenna pattern region (wiring pattern region) 20arranged on the substrate 11; and a dummy pattern region 30 arrangedaround the antenna pattern region 20 on the substrate 11. Further, apower feeding unit 40 is electrically connected to the antenna patternregion 20.

Among them, the substrate 11 has a substantially rectangular shape in aplan view, and has a longitudinal direction parallel to the Y directionand a lateral direction parallel to the X direction. The substrate 11has transparency and a substantially flat shape, and has a substantiallyuniform thickness as a whole. A length L₁ of the substrate 11 in thelongitudinal direction (Y direction) can be selected, for example, in arange of 100 mm or more and 200 mm or less, and a length L₂ of thesubstrate 11 in the lateral direction (X direction) can be selected, forexample, in a range of 50 mm or more and 100 mm or less.

It is sufficient that a material of the substrate 11 is a materialhaving transparency and an electrical insulating property in a visiblelight region. In the present embodiment, the material of the substrate11 is polyethylene terephthalate, but is not limited thereto. As thematerial of the substrate 11, it is preferable to use, for example, anorganic insulating material such as a polyester resin such aspolyethylene terephthalate, an acrylic resin such aspomethylmethacrylate, a polycarbonate resin, a polyimide resin, apolyolefin resin such as a cycloolefin polymer, and a cellulosic resinmaterial such as triacetyl cellulose. Further, glass, ceramics, or thelike can be appropriately selected as the material of the substrate 11according to the application. Note that the example in which thesubstrate 11 is constituted by a single layer is illustrated, but astructure in which a plurality of base materials or layers are stackedmay be adopted without being limited thereto. Further, the substrate 11may be in the form of a film or a plate. Thus, the thickness of thesubstrate 11 is not particularly limited and can be appropriatelyselected according to the application, and a thickness (in the Zdirection) T₁ of the substrate 11 (see FIG. 20) can be set, for example,in a range of 10 μm or more and 200 μm or less in one example.

In FIG. 18, a plurality of (three) antenna pattern regions 20 are formedon the substrate 11 and correspond to different frequency bands,respectively. In other words, the plurality of antenna pattern regions20 have different lengths (lengths in the Y direction) L_(a), and havethe lengths corresponding to specific frequency bands, respectively.Note that the length L_(a) of the antenna pattern region 20 increases asthe corresponding frequency band is lower. When the wiring board 10 isarranged on a display 91 of an image display device 90 (see FIG. 24 tobe described later), for example, each of the antenna pattern regions 20may correspond to any of a telephone antenna, a WiFi antenna, a 3Gantenna, a 4G antenna, an LTE antenna, a Bluetooth (registeredtrademark) antenna, an NFC antenna, and the like in the case of havingthe radio wave transmission/reception function. Alternatively, when thewiring board 10 does not have the radio wave transmission/receptionfunction, and each of the wiring pattern regions 20 may serve afunction, for example, hovering (a function that enables operationwithout requiring a user to directly touch a display), fingerprintauthentication, a heater, noise cut (shield), or the like

Each of the antenna pattern regions 20 is substantially rectangular in aplan view. Each of the antenna pattern regions 20 has a longitudinaldirection parallel to the Y direction and a lateral direction parallelto the X direction. A length L_(a) of each of the antenna patternregions 20 in the longitudinal direction (Y direction) can be selected,for example, in a range of 3 mm or more and 100 mm or less, and a widthW_(a) of each of the antenna pattern regions 20 in the lateral direction(X direction) can be selected, for example, in a range of 1 mm or moreand 10 mm or less.

The antenna pattern region 20 has metal lines formed in a lattice shapeor a mesh shape, and has a uniform repetitive pattern in the X directionand the Y direction. That is, as illustrated in FIG. 19, the antennapattern region 20 is configured by repeating an L-shaped unit patternshape 20 a constituted by a portion extending in the X direction (a partof an antenna connection wiring 22 to be described later) and a portionextending in the Y direction (a part of an antenna wiring 21 to bedescribed later).

As illustrated in FIG. 19, each of the antenna pattern regions 20includes the plurality of antenna wirings (wirings) 21 each having afunction as an antenna, and the plurality of antenna connection wirings(connection wirings) 22 that connect the plurality of antenna wirings21. Specifically, the plurality of antenna wirings 21 and the pluralityof antenna connection wirings 22 are integrally formed as a whole toform a regular lattice shape or mesh shape. Each of the antenna wirings21 extends in the direction corresponding to the frequency band of theantenna (Y direction), and each of the antenna connection wirings 22extends in a direction (X direction) orthogonal to the antenna wiring21. The antenna wiring 21 mainly functions as the antenna by having thelength L_(a) (the length of the above-described antenna pattern region20) corresponding to a predetermined frequency band. On the other hand,the antenna connection wiring 22 connects these antenna wirings 21 toeach other, thereby serving a role of suppressing a problem such as thedisconnection of the antenna wiring 21 or failure in electricalconnection between the antenna wiring 21 and the power feeding unit 40.

In each of the antenna pattern regions 20, a plurality of openingportions 23 are formed by being surrounded by the antenna wirings 21adjacent to each other and the antenna connection wirings 22 adjacent toeach other. Further, the antenna wiring 21 and the antenna connectionwiring 22 are arranged at equal intervals from each other. That is, theplurality of antenna wirings 21 are arranged at equal intervals fromeach other, and a pitch P₁ thereof can be set, for example, in a rangeof 0.01 mm or more and 1 mm or less. Further, the plurality of antennaconnection wirings 22 are arranged at equal intervals to each other, anda pitch P₂ thereof can be set, for example, in a range of 0.01 mm ormore and 1 mm or less. Since the plurality of antenna wirings 21 and theplurality of antenna connection wirings 22 are arranged at equalintervals in this manner, there is no variation in size of the openingportion 23 in each of the antenna pattern regions 20, and it is possibleto make the antenna pattern region 20 less visible with the naked eye.Further, the pitch P₁ of the antenna wiring 21 is equal to the pitch P₂of the antenna connection wiring 22. Thus, each of the opening portions23 has a substantially square shape in a plan view, and the substrate 11having transparency is exposed from each of the opening portions 23.Thus, the transparency as the entire wiring board 10 can be increased byincreasing the area of each of the opening portions 23. Note that alength L₃ of one side of each of the opening portions 23 can be set, forexample, in a range of 0.01 μm or more and 1 μm or less. Note that theantenna wirings 21 and the antenna connection wirings 22 are orthogonalto each other, but are not limited thereto, and may intersect with eachother at an acute angle or an obtuse angle. Further, a shape of theopening portion 23 preferably has the same shape and the same size overthe entire surface, but is not necessarily uniform over the entiresurface, for example, depending on a location.

As illustrated in FIG. 20, each of the antenna wirings 21 has asubstantially rectangular shape or a substantially square shape in across section perpendicular to the longitudinal direction (a crosssection in the X direction). In this case, a cross-sectional shape ofthe antenna wiring 21 is substantially uniform along the longitudinaldirection (Y direction) of the antenna wiring 21. Further, asillustrated in FIG. 21, a shape of a cross section (cross section in theY direction) perpendicular to the longitudinal direction of each of theantenna connection wirings 22 is a substantially rectangular shape or asubstantially square shape, and is substantially the same as the shapeof the cross section (cross section in the X direction) of the antennawiring 21 described above. In this case, the cross-sectional shape ofthe antenna connection wiring 22 is substantially uniform along thelongitudinal direction (X direction) of the antenna connection wiring22. The cross-sectional shapes of the antenna wiring 21 and the antennaconnection wiring 22 are not necessarily the substantially rectangularshape or the substantially square shape, and may be, for example, asubstantially trapezoidal shape in which the front surface side(positive side in the Z direction) is narrower than the back surfaceside (negative side in the Z direction), or a shape in which sidesurfaces located on both sides in the longitudinal direction are curved.

In the present embodiment, a line width W₁ of the antenna wiring 21 (alength in the X direction, see FIG. 20) and a line width W₂ of theantenna connection wiring 22 (a length in the Y direction, see FIG. 21)are not particularly limited, and can be appropriately selectedaccording to the application. For example, the line width W₁ of theantenna wiring 21 can be selected in a range of 0.1 μm or more and 5.0μm or less, and the line width W₂ of the antenna connection wiring 22can be selected in a range of 0.1 μm or more and 5.0 μm or less.Further, a height H₁ of the antenna wiring 21 (a length in the Zdirection, see FIG. 20) and a height H₂ of the antenna connection wiring22 (a length in the Z direction, see FIG. 21) are not particularlylimited, and can be appropriately selected according to the application,and, for example, can be selected in a range of 0.1 μm or more and 5.0μm or less.

It is sufficient that each material of the antenna wiring 21 and theantenna connection wiring 22 is a metal material having a conductivity.In the present embodiment, the materials of the antenna wiring 21 andthe antenna connection wiring 22 are copper, but are not limitedthereto. As the materials of the antenna wiring 21 and the antennaconnection wiring 22, for example, a metal material (including an alloy)such as gold, silver, copper, platinum, tin, aluminum, iron, and nickelcan be used.

Referring again to FIG. 18, the dummy pattern region 30 is provided soas to surround the periphery of each of the antenna pattern regions 20,and is formed to surround the entire circumferential region (thepositive side in the X direction, the negative side in the X direction,and the positive side in the Y direction) excluding the power feedingunit 40 side (the negative side in the Y direction) in each of theantenna pattern regions 20. In this case, the dummy pattern region 30 isarranged on the substrate 11 and over substantially the entire regionexcluding the antenna pattern region 20 and the power feeding unit 40.The dummy pattern region 30 does not substantially function as anantenna, which is different from the antenna pattern region 20.

As illustrated in FIG. 19, the dummy pattern region 30 is configured byrepeating a dummy wiring 30 a having a predetermined unit pattern shape.That is, the dummy pattern region 30 includes a plurality of the dummywirings 30 a each having the same shape, and each of the dummy wirings30 a is electrically independent of the antenna pattern region 20 (theantenna wiring 21 and the antenna connection wiring 22). Further, theplurality of dummy wirings 30 a are regularly arranged over the entireregion of the dummy pattern region 30. The plurality of dummy wirings 30a are spaced apart from each other in a plane direction, and arearranged in an island shape to protrude above the substrate 11. That is,each of the dummy wirings 30 a is electrically independent of theantenna pattern region 20, the power feeding unit 40, and the otherdummy wirings 30 a. Each of the dummy wirings 30 a is substantially Lshape in a plan view, and has a first dummy wiring portion 31 extendingin the Y direction and a second dummy wiring portion 32 extending in theX direction. Among these, the first dummy wiring portion 31 has apredetermined length L₄ (length in the Y direction), and the seconddummy wiring portion 32 has a predetermined length L₅ (length in the Xdirection), and these lengths are equal (L₄=L₅).

A void portion 33 a is formed between the dummy wirings 30 a adjacent toeach other in the X direction, and a void portion 33 b is formed betweenthe dummy wirings 30 a adjacent to each other in the Y direction. Inthis case, the dummy wirings 30 a are arranged at equal intervals. Thatis, the dummy wirings 30 a adjacent to each other in the X direction arearranged at equal intervals, and a gap G₁ thereof can be set, forexample, in a range of 1 μm or more and 20 μm or less. Similarly, thedummy wirings 30 a adjacent to each other in the Y direction arearranged at equal intervals, and a gap G₂ thereof can be set, forexample, in a range of 1 μm or more and 20 μm or less. Note that themaximum values of the gaps G₁ and G₂ may be 0.8 times or less of theabove-described pitches P₁ and P₂, respectively. In this case, the gapG₁ of the dummy wirings 30 a in the X direction is equal to the gap G₂of the dummy wirings 30 a in the Y direction (G₁=G₂).

In the present embodiment, the dummy wiring 30 a has a shape in which apart of the above-described unit pattern shape 20 a of the antennapattern region 20 is missing. That is, the shape of the dummy wiring 30a is a shape obtained by removing the above-described void portions 33 aand 33 b from the L-shaped unit pattern shape 20 a of the antennapattern region 20. That is, the shape in which the plurality of dummywirings 30 a of the dummy pattern region 30 and the plurality of voidportions 33 a and 33 b are combined corresponds to the lattice shape orthe mesh shape forming the antenna pattern region 20. Since the dummywiring 30 a of the dummy pattern region 30 is formed into the shape inwhich a part of the unit pattern shape 20 a of the antenna patternregion 20 is missing in this manner, it is possible to make it difficultto visually recognize a difference between the antenna pattern region 20and the dummy pattern region 30, and to make the antenna pattern region20 arranged on the substrate 11 hardly visible.

In FIG. 19, the antenna pattern region 20 and the dummy pattern region30 are adjacent to each other in the Y direction. The first dummy wiringportion 31 is formed on an extension of the antenna wiring 21 near aboundary between the antenna pattern region 20 and the dummy patternregion 30. Thus, it is difficult to visually recognize the differencebetween the antenna pattern region 20 and the dummy pattern region 30.Further, for the same reason, it is preferable that the second dummywiring portion 32 be formed on an extension of the antenna connectionwiring 22 even in a place where the antenna pattern region 20 and thedummy pattern region 30 are adjacent to each other in the X directionalthough not illustrated.

As illustrated in FIG. 22, the first dummy wiring portion 31 of each ofthe dummy wirings 30 a has a substantially rectangular or substantiallysquare cross section (cross section in the X direction) perpendicular toa longitudinal direction thereof (the Y direction). As illustrated inFIG. 21, the second dummy wiring portion 32 of each of the dummy wirings30 a has a substantially rectangular or substantially square crosssection (cross section in the Y direction) perpendicular to alongitudinal direction thereof (the X direction). In this case, thecross-sectional shape of the first dummy wiring portion 31 issubstantially the same as the cross-sectional shape of the antennawiring 21, and the sectional shape of the second dummy wiring portion 32is substantially the same as the sectional shape of the antennaconnection wiring 22.

In the present embodiment, a line width W₃ of the first dummy wiringportion 31 (a length in the X direction, see FIG. 22) is substantiallythe same as the line width W₁ of the antenna wiring 21, and a line widthW₄ of the second dummy wiring portion 32 (a length in the Y direction,see FIG. 21) is substantially the same as the line width W₂ of theantenna connection wiring 22. Further, a height H₃ of the first dummywiring portion 31 (a length in the Z direction, see FIG. 22) and aheight H₄ of the second dummy wiring portion 32 (a length in the Zdirection, see FIG. 21) are substantially the same as the height H₁ ofthe antenna wiring 21 and the height H₂ of the antenna connection wiring22, respectively.

As a material of the dummy wiring 30 a, the same metal material as thematerial of the antenna wiring 21 and the material of the antennaconnection wiring 22 can be used.

Meanwhile, in the present embodiment, the antenna pattern region 20 andthe dummy pattern region 30 have predetermined aperture ratios A1 andA2, respectively. Among these, the aperture ratio A1 of the antennapattern region 20 can be set, for example, in a range of 85% or more and99.9% or less. Further, the aperture ratio A2 of the dummy patternregion 30 can be set, for example, in a range of 87% or more and lessthan 100%. In this case, the aperture ratio A2 of the dummy patternregion 30 is higher than the aperture ratio A1 of the antenna patternregion 20 (A2>A1). As a result, the transparency of the wiring board 10can be ensured. Note that the configuration is not limited thereto, andthe aperture ratio A2 of the dummy pattern region 30 may be lower thanthe aperture ratio A1 of the antenna pattern region 20 (A2<A1).

Further, a difference between the aperture ratio A2 of the dummy patternregion 30 and the aperture ratio A1 of the antenna pattern region 20(|A2−A1|) is preferably in a range of more than 0% and 7% or less, andis more preferably in a range of more than 0% and 1% or less. As thedifference between the aperture ratio A2 of the dummy pattern region 30and the aperture ratio A1 of the antenna pattern region 20 is set to besmall in this manner, the boundary between the antenna pattern region 20and the dummy pattern region 30 can be made hardly visible, and thepresence of the antenna pattern region 20 can be made hardlyrecognizable with the naked eye.

Further, a total aperture ratio A3 of the antenna pattern region 20 andthe dummy pattern region 30 (a combined aperture ratio of the antennapattern region 20 and the dummy pattern region 30) can be set, forexample, in a range of 87% or more and less than 100%. As the totalaperture ratio A3 of the wiring board 10 is set in this range, theconductivity and transparency of the wiring board 10 can be ensured.

Note that the aperture ratio refers to a ratio (%) of an area of anopening region (region where the metal portions such as the antennawiring 21, the antenna connection wiring 22, and the dummy wiring 30 aare not present and the substrate 11 is exposed) accounting for a unitarea of a predetermined region (the antenna pattern region 20, the dummypattern region 30, or the antenna pattern region 20 and the dummypattern region 30).

Referring again to FIG. 18, the power feeding unit 40 is electricallyconnected to the antenna pattern region 20. The power feeding unit 40 ismade of a conductive thin plate member having a substantiallyrectangular shape. A longitudinal direction of the power feeding unit 40is parallel to the X direction, and a lateral direction of the powerfeeding unit 40 is parallel to the Y direction. Further, the powerfeeding unit 40 is arranged at a longitudinal end of the substrate 11(an end on the negative side in the Y direction). As a material of thepower feeding unit 40, for example, a metal material (including analloy) such as gold, silver, copper, platinum, tin, aluminum, iron, andnickel can be used. The power feeding unit 40 is electrically connectedto the wireless communication circuit 92 of the image display device 90when the wiring board 10 is incorporated in the image display device 90(see FIG. 24). Note that the power feeding unit 40 is provided on thefront surface of the substrate 11, but is not limited thereto, and thepower feeding unit 40 may be partially or entirely located outside aperipheral edge of the substrate 11.

[Method for Manufacturing Wiring Board]

Next, a method for manufacturing the wiring board according to thepresent embodiment will be described with reference to FIGS. 23(a) to23(h). FIGS. 23(a) to 23(h) are cross-sectional views illustrating themethod for manufacturing the wiring board according to the presentembodiment.

First, the substrate 11 is prepared, and a conductive layer 51 is formedon substantially the entire front surface of the substrate 11 asillustrated in FIG. 23(a). In the present embodiment, a thickness of theconductive layer 51 is 200 nm. However, the thickness of the conductivelayer 51 can be appropriately selected in a range of 10 nm or more and1000 nm or less without being limited thereto. In the presentembodiment, the conductive layer 51 is formed by a sputtering methodusing copper. As a method for forming the conductive layer 51, a plasmaCVD method may be used.

Next, a photocurable insulating resist 52 is supplied to substantiallythe entire front surface of the substrate 11 as illustrated in FIG.23(b). Examples of the photocurable insulating resist 52 include anorganic resin such as an epoxy resin.

Subsequently, a transparent mold 53 for imprinting having a protrusion53 a is prepared (FIG. 23(c)), and the mold 53 and the substrate 11 arebrought close to each other, and the photocurable insulating resist 52is developed between the mold 53 and the substrate 11. Next, lightirradiation is performed from the mold 53 side to cure the photocurableinsulating resist 52, thereby forming an insulating layer 54. As aresult, a trench 54 a having a shape in which the protrusion 53 a hasbeen transferred is formed on a front surface of the insulating layer54. The trench 54 a has a planar shape pattern corresponding to theantenna wiring 21, the antenna connection wiring 22, and the dummywiring 30 a.

Thereafter, the mold 53 is separated from the insulating layer 54 toobtain the insulating layer 54 having a cross-sectional structureillustrated in FIG. 23(d). A direction in which the mold 53 is separatedfrom the insulating layer 54 is preferably the Y direction in which thelonger antenna wiring 21 extends.

As the trench 54 a is formed on the front surface of the insulatinglayer 54 by the imprinting method in this manner, a fine shape of thetrench 54 a can be made. Note that the insulating layer 54 may be formedby a photolithography method without being limited thereto. In thiscase, a resist pattern is formed by the photolithography method so as toexpose the conductive layer 51 corresponding to the antenna wiring 21,the antenna connection wiring 22, and the dummy wiring 30 a.

As illustrated in FIG. 23(d), a residue of an insulating material mayremain at a bottom of the trench 54 a of the insulating layer 54. Thus,the residue of the insulating material is removed by performing a wettreatment using a permanganate solution or N-methyl-2-pyrrolidone or adry treatment using oxygen plasma. As the residue of the insulatingmaterial is removed in this manner, the trench 54 a exposing theconductive layer 51 can be formed as illustrated in FIG. 23(e).

Next, the trench 54 a of the insulating layer 54 is filled with aconductor 55 as illustrated in FIG. 23(f). In the present embodiment,the trench 54 a of the insulating layer 54 is filled with copper by anelectrolytic plating method using the conductive layer 51 as a seedlayer.

Subsequently, the insulating layer 54 is removed as illustrated in FIG.23(g). In this case, the wet treatment using a permanganate solution orN-methyl-2-pyrrolidone or the dry treatment using oxygen plasma isperformed to remove the insulating layer 54 on the substrate 11.

Thereafter, the conductive layer 51 on the front surface of thesubstrate 11 is removed as illustrated in FIG. 23(h). At this time, theconductive layer 51 is etched so as to expose the front surface of thesubstrate 11 by performing a wet process using a hydrogen peroxidesolution. In this manner, the wiring board 10, which includes thesubstrate 11, the antenna pattern region 20 and the dummy pattern region30 arranged on the substrate 11, is obtained. In this case, the antennapattern region 20 includes the antenna wiring 21 and the antennaconnection wiring 22, and the dummy pattern region 30 includes the dummywiring 30 a. The above-described conductor 55 includes the antennawiring 21, the antenna connection wiring 22, and the dummy wiring 30 a.

[Operation of Present Embodiment]

Next, an operation of the wiring board having such a configuration willbe described.

As illustrated in FIG. 24, the wiring board 10 is incorporated in animage display device 90 including the display 91. The wiring board 10 isarranged on the display 91. Examples of such an image display device 90include a mobile terminal device such as a smartphone and a tablet. Theantenna pattern region 20 of the wiring board 10 is electricallyconnected to the wireless communication circuit 92 of the image displaydevice 90 via the power feeding unit 40. In this manner, radio waves ofa predetermined frequency can be transmitted and received via theantenna pattern region 20 so that communication can be performed usingthe image display device 90. Note that the dummy pattern region 30 isseparated from the antenna pattern region 20 and is electricallyindependent, and thus, there is no possibility that the transmission andreception of radio waves are affected by the provision of the dummypattern region 30.

According to the present embodiment, the wiring board 10 includes: thesubstrate 11 having transparency and the antenna pattern region 20including the plurality of antenna wirings 21 each of which is arrangedon the substrate 11 and has the function as the antenna, and thus, thetransparency of the wiring board 10 is ensured. As a result, when thewiring board 10 is arranged on the display 91, the display 91 can beseen through the opening portion 23 of the antenna pattern region 20, sothat the visibility of the display 91 is not hindered.

Further, the dummy pattern region 30 including the plurality of dummywirings 30 a electrically independent of the antenna wiring 21 isarranged around the antenna pattern region 20 according to the presentembodiment. Since the dummy pattern region 30 is arranged around theantenna pattern region 20 in this manner, a boundary between the antennapattern region 20 and the other region can be made obscure. As a result,it is possible to make the antenna pattern region 20 hardly visible onthe front surface of the display 91, and to make it difficult for a userof the image display device 90 to recognize the antenna pattern region20 with the naked eye.

Further, according to the present embodiment, each of the antennapattern region 20 and the dummy pattern region 30 is formed by repeatingthe predetermined unit pattern shape, and the unit pattern shape (thedummy wiring 30 a) of the dummy pattern region 30 is the shape in whicha part of the unit pattern shape 20 a of the antenna pattern region 20is missing. As a result, it is possible to make the boundary between theantenna pattern region 20 and the dummy pattern region 30 obscure, andto make it difficult to recognize the antenna pattern region 20 with thenaked eye on the front surface of the display 91.

Further, the aperture ratio A2 of the dummy pattern region 30 is higherthan the aperture ratio A1 of the antenna pattern region 20 according tothe present embodiment. As a result, it is possible to ensure thetransparency of the wiring board 10 while making it difficult torecognize the antenna pattern region 20.

Further, the antenna pattern region 20 includes the plurality of antennaconnection wirings 22 connecting the plurality of antenna wirings 21according to the present embodiment. As a result, it is possible to makethe disconnection of the antenna wiring 21 difficult, and to suppress adecrease in the function of the antenna wiring 21 as the antenna.

[Modifications]

Next, various modifications of the wiring board will be described withreference to FIGS. 25 to 37. FIGS. 25 to 37 are views illustrating thevarious modifications of the wiring board. The respective modificationsillustrated in FIGS. 25 to 37 are different in terms of theconfiguration of the antenna pattern region 20 and/or the dummy patternregion 30, and the other configurations thereof are substantially thesame as those of the above-described embodiment. In FIGS. 25 to 37, thesame portions as those of the modes illustrated in FIG. 18 to FIG. 24are denoted by the same reference signs, and detailed descriptionsthereof will be omitted.

[First Modification]

FIG. 25 illustrates a wiring board 10A according to a firstmodification. In FIG. 25, the dummy pattern region 30 of the wiringboard 10A includes the plurality of dummy wirings 30 a each having apredetermined unit pattern shape. Each of the dummy wirings 30 a iselectrically independent of the antenna pattern region 20 (the antennawiring 21 and the antenna connection wiring 22). Each of the dummywirings 30 a has the first dummy wiring portion 31 extending in the Ydirection and the second dummy wiring portion 32 extending in the Xdirection. In this case, the first dummy wiring portion 31 and thesecond dummy wiring portion 32 of each of the dummy wirings 30 a arearranged apart from each other in a plane direction.

The void portion 33 c is formed between the first dummy wiring portion31 and the second dummy wiring portion 32 of each of the dummy wirings30 a. Further, when assuming a case where the dummy wiring 30 a issupplemented with the void portion 33 c, the void portions 33 a and 33 bare formed, respectively, between the dummy wirings 30 a adjacent toeach other in the X direction and between the dummy wirings 30 aadjacent to each other in the Y direction.

The dummy wiring 30 a in the dummy pattern region 30 has a shape inwhich a part of the unit pattern shape 20 a in the antenna patternregion 20 is missing. That is, the shape of the dummy wiring 30 a is ashape obtained by removing the void portions 33 a, 33 b, and 33 c fromthe L-shaped unit pattern shape 20 a of the antenna pattern region 20.Note that the aperture ratio A2 of the dummy pattern region 30 can beset, for example, in a range of 85% or more and less than 100%.

As the first dummy wiring portion 31 and the second dummy wiring portion32 of each of the dummy wirings 30 a are arranged apart from each otherin the plane direction in this manner, an aperture ratio of the dummypattern region 30 can be further increased, and the transparency of thewiring board 10A can be improved.

[Second Modification]

FIG. 26 illustrates a wiring board 1013 according to a secondmodification. In FIG. 26, the dummy pattern region 30 of the wiringboard 1013 includes the plurality of dummy wirings 30 a each having apredetermined unit pattern shape. Each of the dummy wirings 30 a iselectrically independent of the antenna pattern region 20 (the antennawiring 21 and the antenna connection wiring 22). The dummy wiring 30 ahas the first dummy wiring portion 31 and the second dummy wiringportion 32 extending obliquely with respect to the X direction and the Ydirection, respectively. The first dummy wiring portion 31 and thesecond dummy wiring portion 32 of each of the dummy wirings 30 a arearranged apart from each other in a plane direction. In this case, alongitudinal direction of the first dummy wiring portion 31 is arrangedto be inclined by 45° with respect to a longitudinal direction of theantenna wiring 21. Further, a longitudinal direction of the second dummywiring portion 32 is located in a direction orthogonal to thelongitudinal direction of the first dummy wiring portion 31. Note thatthe aperture ratio A2 of the dummy pattern region 30 can be set, forexample, in a range of 85% or more and less than 100%.

As the first dummy wiring portion 31 and the second dummy wiring portion32 of each of the dummy wirings 30 a are arranged obliquely with respectto the antenna wiring 21 in this manner, it is possible to suppressgeneration of an interference fringe caused by a diffraction grating.

[Third Modification]

FIG. 27 illustrates a wiring board 10C according to a thirdmodification. In FIG. 27, the antenna pattern region 20 of the wiringboard 10C includes the plurality of antenna wirings 21 each having afunction as an antenna and the plurality of antenna connection wirings22 that connect the plurality of antenna wirings 21. In this case, thepitch P₁ of the antenna wiring 21 is smaller than the pitch P₂ of theantenna connection wiring 22 (P₁<P₂). The pitch P₁ of the antenna wiring21 can be set, for example, in a range of 0.01 mm or more and 1 mm orless, and the pitch P₂ of the antenna connection wiring 22 can be set,for example, in a range of 0.03 mm or more and 1 mm or less. Each of theopening portions 23 has a substantially rectangular shape that is longerin the Y direction than in the X direction in a plan view. As describedabove, the transparency of the entire wiring board 10C can be furtherincreased by increasing the area of each of the opening portions 23.

Further, the dummy pattern region 30 includes the plurality of dummywirings 30 a each having a predetermined unit pattern shape. Each of thedummy wirings 30 a is electrically independent of the antenna patternregion 20 (the antenna wiring 21 and the antenna connection wiring 22).The dummy wiring 30 a includes a pair of first dummy wiring portions 31a and 31 b each extending in the Y direction, and the second dummywiring portion 32 extending in the X direction. In this case, the firstdummy wiring portion 31 a, the first dummy wiring portion 31 b, and thesecond dummy wiring portion 32 of each of the dummy wirings 30 a arearranged apart from each other in a plane direction.

The void portion 33 c is formed between the first dummy wiring portion31 a and the second dummy wiring portion 32 of each of the dummy wirings30 a. Further, a void portion 33 d is formed between the first dummywiring portions 31 a and 31 b. Furthermore, when assuming a case wherethe dummy wiring 30 a is supplemented with the void portions 33 c and 33d, the void portions 33 a and 33 b are formed, respectively, between thedummy wirings 30 a adjacent to each other in the X direction and betweenthe dummy wirings 30 a adjacent to each other in the Y direction. Inthis case, the dummy wiring 30 a in the dummy pattern region 30 has ashape in which a part of the unit pattern shape 20 a in the antennapattern region 20 is missing. That is, the shape of the dummy wiring 30a is a shape obtained by removing the void portions 33 a to 33 d fromthe L-shaped unit pattern shape 20 a of the antenna pattern region 20.Note that the aperture ratio A2 of the dummy pattern region 30 can beset, for example, in a range of 90% or more and less than 100%.

The transparency of the wiring board 10C can be improved by increasingan opening region of the antenna pattern region 20 and the dummy patternregion 30 (a region where metal portions such as the antenna wiring 21,the antenna connection wiring 22, and the dummy wiring 30 a are notpresent and the substrate 11 is exposed) in this manner.

[Fourth Modification]

FIG. 28 illustrates a wiring board 10D according to a fourthmodification. In FIG. 28, the dummy pattern region 30 of the wiringboard 10D includes the plurality of dummy wirings 30 a each having apredetermined unit pattern shape. Each of the dummy wirings 30 a iselectrically independent of the antenna pattern region 20 (the antennawiring 21 and the antenna connection wiring 22). The dummy wiring 30 aincludes the pair of first dummy wiring portions 31 a and 31 b extendingobliquely with respect to the X direction and the Y direction,respectively, and the second dummy wiring portion 32 extending obliquelywith respect to the X direction and the Y direction. The first dummywiring portion 31 a, the first dummy wiring portion 31 b, and the seconddummy wiring portion 32 of each of the dummy wirings 30 a are arrangedapart from each other in a plane direction. In this case, longitudinaldirections of the pair of first dummy wiring portions 31 a and 31 b arearranged to be inclined by 45° with respect to a longitudinal directionof the antenna wiring 21. Further, a longitudinal direction of thesecond dummy wiring portion 32 is located in a direction orthogonal tothe longitudinal direction of each of the first dummy wiring portions 31a and 31 b. Note that the aperture ratio A2 of the dummy pattern region30 can be set, for example, in a range of 90% or more and less than100%.

As the first dummy wiring portions 31 a and 31 b and the second dummywiring portion 32 of each of the dummy wirings 30 a are arrangedobliquely with respect to the antenna wiring 21 in this manner, it ispossible to suppress generation of an interference fringe caused by adiffraction grating.

[Fifth Modification]

FIG. 29 illustrates a wiring board 10E according to a fifthmodification. In FIG. 29, the dummy pattern region 30 of the wiringboard 10E includes the plurality of dummy wirings 30 a each having apredetermined unit pattern shape. Each of the dummy wirings 30 a iselectrically independent of the antenna pattern region 20 (the antennawiring 21 and the antenna connection wiring 22). The dummy wiring 30 aincludes a plurality of (four) first dummy wiring portions 31 c eachextending in the Y direction and a plurality of (four) second dummywiring portions 32 c extending in the X direction. In this case, theplurality of first dummy wiring portions 31 c are arranged apart fromeach other in the Y direction, and the plurality of second dummy wiringportions 32 c are arranged apart from each other in the X direction.

A void portion 33 e is formed at an intersection portion between thefirst dummy wiring portion 31 a and the second dummy wiring portion 32 cof the dummy wiring 30 a. Further, a void portion 33 f is formed betweenthe plurality of first dummy wiring portions 31 c. Further, a voidportion 33 g is formed between each of the plurality of second dummywiring portions 32 c. In this case, the dummy wiring 30 a in the dummypattern region 30 has a shape in which a part of the unit pattern shape20 a in the antenna pattern region 20 is missing. That is, the shape ofthe dummy wiring 30 a is a shape obtained by removing the void portions33 e to 33 g from the L-shaped unit pattern shape 20 a of the antennapattern region 20.

In the present modification, an additional pattern 34 apart from thedummy wiring 30 a of the dummy pattern region 30 is arranged in thedummy pattern region 30. In this case, the additional pattern 34 isarranged apart from the plurality of first dummy wiring portions 31 cand the plurality of second dummy wiring portions 32 c in both the Xdirection and the Y direction. In this case, each of the additionalpatterns 34 extends linearly in parallel with the Y direction. Further,a plurality of (four) additional patterns 34 are arranged for one dummywiring 30 a. It is preferable that the total area of the plurality of(four) additional patterns 34 be close to the area of the void portions33 e to 33 g of each of the dummy wirings 30 a. Note that a material ofthe additional pattern 34 can be the same metal material as the materialof the dummy wiring 30 a.

As the additional pattern 34 is arranged in the dummy pattern region 30in this manner, a difference (|A2−A1|) between the aperture ratio A2 ofthe dummy pattern region 30 and the aperture ratio A1 of the antennapattern region 20 can be made close to zero. Specifically, thedifference between the aperture ratio A2 and the aperture ratio A1 canbe set in a range of 0% or more and 1% or less. As a result, it ispossible to make the boundary between the antenna pattern region 20 andthe dummy pattern region 30 obscure, and to make it difficult torecognize the antenna pattern region 20 with the naked eye.

[Sixth Modification]

FIG. 30 illustrates a wiring board 10F according to a sixthmodification. In FIG. 30, the additional patterns 34 apart from thedummy wiring 30 a of the dummy pattern region 30 are arranged in thedummy pattern region 30. In this case, each of the additional patterns34 extends linearly to be inclined with respect to each of the Xdirection and the Y direction. In FIG. 30, a plurality of (four)additional patterns 34 are arranged for one dummy wiring 30 a. The otherconfigurations are substantially the same as those of the wiring board10E (fifth modification) illustrated in FIG. 29.

[Seventh Modification]

FIG. 31 illustrates a wiring board 10G according to a seventhmodification. In FIG. 31, the dummy wiring 30 a includes a plurality of(two) first dummy wiring portions 31 c each extending in the Y directionand a plurality of (two) second dummy wiring portions 32 c extending inthe X direction. Further, each of the additional patterns 34 extendslinearly to be inclined with respect to each of the X direction and theY direction. In this case, a plurality of (two) additional patterns 34are arranged for one dummy wiring 30 a. The other configurations aresubstantially the same as those of the wiring board 10E (fifthmodification) illustrated in FIG. 29.

[Eighth Modification]

FIG. 32 illustrates a wiring board 10H according to an eighthmodification. In FIG. 32, the dummy wiring 30 a includes the pluralityof (two) first dummy wiring portions 31 c each extending in the Ydirection and the plurality of (two) second dummy wiring portions 32 cextending in the X direction. Among them, one first dummy wiring portion31 c and one second dummy wiring portion 32 c are connected to eachother to form an L-shaped portion in a plan view. In this case, each ofthe additional patterns 34 extends linearly in parallel with respect tothe Y direction. Further, a plurality of (two) additional patterns 34are arranged for one dummy wiring 30 a. The other configurations aresubstantially the same as those of the wiring board 10E (fifthmodification) illustrated in FIG. 29.

[Ninth Modification]

FIG. 33 illustrates a wiring board 10I according to a ninthmodification. In FIG. 33, each of the additional patterns 34 extendslinearly to be inclined with respect to each of the X direction and theY direction. In this case, a plurality of (two) additional patterns 34are arranged for one dummy wiring 30 a. The other configurations aresubstantially the same as those of the wiring board 10H (eighthmodification) illustrated in FIG. 32.

[Tenth Modification]

FIG. 34 illustrates a wiring board 10J according to a tenthmodification. In FIG. 34, each of the additional patterns 34 has a crossshape in a plan view. In this case, one additional pattern 34 isarranged for one dummy wiring 30 a. The other configurations aresubstantially the same as those of the wiring board 10E (fifthmodification) illustrated in FIG. 29.

[Eleventh Modification]

FIG. 35 illustrates a wiring board 10K according to an eleventhmodification. In FIG. 35, each of the additional patterns 34 has a dotshape in a plan view. In this case, a plurality of dot-shaped additionalpatterns 34 are arranged for one dummy wiring 30 a, and the plurality ofadditional patterns 34 are aligned in both the X direction and the Ydirection. The other configurations are substantially the same as thoseof the wiring board 10G (seventh modification) illustrated in FIG. 31.

[Twelfth Modification]

FIG. 36 illustrates a wiring board 10L according to a twelfthmodification. In FIG. 36, each of the additional patterns 34 has a crossshape in a plan view. In this case, one additional pattern 34 isarranged for one dummy wiring 30 a. The other configurations aresubstantially the same as those of the wiring board 10H (eighthmodification) illustrated in FIG. 32.

[Thirteenth Modification]

FIG. 36 illustrates a wiring board 10M according to a thirteenthmodification. In FIG. 36, each of the additional patterns 34 has a dotshape in a plan view. In this case, a plurality of dot-shaped additionalpatterns 34 are arranged for one dummy wiring 30 a, and the plurality ofadditional patterns 34 are aligned in both the X direction and the Ydirection. The other configurations are substantially the same as thoseof the wiring board 10H (eighth modification) illustrated in FIG. 32.

Note that the additional pattern 34 may be provided in the dummy patternregion 30 even in each of the wiring boards 10 and 10A to 10Dillustrated in FIGS. 18 to 28 although not illustrated.

Third Embodiment

Next, a third embodiment will be described with reference to FIGS. 38 to51. FIGS. 38 to 51 are views illustrating the third embodiment. In FIGS.38 to 51, the same portions as those of the second embodimentillustrated in FIG. 18 to FIG. 37 are denoted by the same referencesigns, and detailed descriptions thereof will be omitted.

[Configuration of Wiring Board]

A configuration of the wiring board according to the present embodimentwill be described with reference to FIGS. 38 to 42. FIGS. 38 to 42 areviews illustrating the wiring board according to the present embodiment.

As illustrated in FIG. 38, the wiring board 10 according to the presentembodiment is arranged, for example, on a display of an image displaydevice. Such a wiring board 10 includes the substrate 11 havingtransparency and the antenna pattern region 20 arranged on the substrate11. Further, a power feeding unit 40 is electrically connected to theantenna pattern region 20.

The configuration of the substrate 11 is substantially the same as thatin the case of the second embodiment.

Each of the antenna pattern regions 20 is substantially rectangular in aplan view. Each of the antenna pattern regions 20 has a longitudinaldirection parallel to the Y direction and a lateral direction (widthdirection) parallel to the X direction. The length L_(a) of each of theantenna pattern regions 20 in the longitudinal direction (Y direction)can be selected, for example, in a range of 3 mm or more and 100 mm orless, and the width W_(a) of each of the antenna pattern regions 20 inthe lateral direction (width direction) can be selected, for example, ina range of 1 mm or more and 10 mm or less.

The antenna pattern region 20 has metal lines formed in a lattice shapeor a mesh shape, and has a repetitive pattern in the X direction and theY direction. That is, the antenna pattern region 20 is configured byrepeating the L-shaped unit pattern shape 20 a (see FIG. 40) constitutedby a portion extending in the X direction (a part of the antennaconnection wiring 22 to be described later) and a portion extending inthe Y direction (a part of the antenna wiring 21 to be described later).

As illustrated in FIG. 39, each of the antenna pattern regions 20includes the plurality of antenna wirings 21 each having a function asan antenna and the plurality of antenna connection wirings 22 thatconnect the plurality of antenna wirings 21. Specifically, the pluralityof antenna wirings 21 and the plurality of antenna connection wirings 22are integrally formed as a whole to form a lattice shape or a meshshape. Each of the antenna wirings 21 extends in the directioncorresponding to the frequency band of the antenna (the longitudinaldirection and the Y direction), and each of the antenna connectionwirings 22 extends in a direction (the width direction and the Xdirection) orthogonal to the antenna wiring 21. The antenna wiring 21mainly functions as the antenna by having the length L_(a) (the lengthof the above-described antenna pattern region 20, see FIG. 38)corresponding to a predetermined frequency band. On the other hand, theantenna connection wiring 22 connects these antenna wirings 21 to eachother, thereby serving a role of suppressing a problem such as thedisconnection of the antenna wiring 21 or failure in electricalconnection between the antenna wiring 21 and the power feeding unit 40.

In each of the antenna pattern regions 20, a plurality of openingportions 23 are formed by being surrounded by the antenna wirings 21adjacent to each other and the antenna connection wirings 22 adjacent toeach other. Further, the antenna pattern region 20 has a central portion20 c in the width direction (X direction) and a pair of edge portions 20e ₁ and 20 e ₂ in the width direction (X direction). The widthwisecentral portion 20 c refers to a portion that is equidistant along thewidth direction from both end edges in the width direction (X direction)of the antenna pattern region 20. Note that each of the widthwisecentral portion 20 c and the widthwise edge portions 20 e ₁ and 20 e ₂may have a certain width (length in the X direction). For example, thewidthwise central portion 20 c and the widthwise edge portions 20 e ₁and 20 e ₂ may be regions each having a width (length in the Xdirection) of about 5% or more and 30% or less of the width W_(a) of theantenna pattern region 20.

As illustrated in FIGS. 40(a) and 40(b), the plurality of antennawirings 21 are arranged at an interval (the pitch P₁) in the widthdirection (X direction) of the antenna pattern region 20. In this case,the plurality of antenna wirings 21 are arranged at intervals differentfrom each other between the central portion 20 c in the width direction(X direction) of the antenna pattern region 20 and the edge portions 20e ₁ and 20 e ₂ in the width direction (X direction). That is, theplurality of antenna wirings 21 are arranged at a wide pitch P_(1A) inthe widthwise central portion 20 c of the antenna pattern region 20, andare arranged at a pitch P_(1B) narrower than the pitch P_(1A) in thewidthwise edge portions 20 e ₁ and 20 e ₂ (P_(1A)>P_(1B)). Note that thepitch P₁ of the plurality of antenna wirings 21 is the widest in thewidthwise central portion 20 c of the antenna pattern region 20 (thepitch P_(1A)), and is the narrowest in the widthwise edge portions 20 e₁ and 20 e ₂ (the pitch P_(1B)). Specifically, the pitch P_(1A) of theantenna wiring 21 in the widthwise central portion 20 c of the antennapattern region 20 can be set, for example, in a range of 0.05 mm or moreand 1 mm or less. The pitch P_(1B) of the antenna wiring 21 in thewidthwise edge portions 20 e ₁ and 20 e ₂ of the antenna pattern region20 can be set, for example, in a range of 0.01 mm or more and 0.3 mm orless.

The pitch P₁ of the plurality of antenna wirings 21 may be graduallychanged from the pitch P_(1B) in each of the widthwise edge portions 20e ₁ and 20 e ₂ to the pitch P_(1A) in the widthwise central portion 20c. Alternatively, the plurality of antenna wirings 21 may be arranged atthe uniform pitch P_(1B) in a region near each of the widthwise edgeportions 20 e ₁ and 20 e ₂, and arranged at the uniform pitch P_(1A) ina region near the widthwise central portion 20 c. Further, the pitchP_(1B) of the antenna wiring 21 in one widthwise edge portion 20 e ₁ isequal to the pitch P_(1B) of the antenna wiring 21 in the otherwidthwise edge portion 20 e ₂ in the present embodiment. However, thepitch P_(1B) of the antenna wiring 21 may be different between the onewidthwise edge portion 20 e ₁ and the other widthwise edge portion 20 e₂ without being limited thereto.

The plurality of antenna connection wirings 22 are arranged at equalintervals in the longitudinal direction (Y direction) of the antennapattern region 20. The pitch P₂ of the plurality of antenna connectionwirings 22 can be set, for example, in a range of 0.01 mm or more and 1mm or less. Each of the opening portions 23 has a substantiallyrectangular shape or a substantially square shape in a plan view, andthe area of the opening portion 23 located on the widthwise centralportion 20 c side is larger than the area of the opening portion 23located on the widthwise edge portions 20 e ₁ and 20 e ₂ side. Further,the substrate 11 having transparency is exposed from each of the openingportions 23. Thus, the transparency as the entire wiring board 10 can beincreased by increasing the area of each of the opening portions 23.Note that the antenna wirings 21 and the antenna connection wirings 22are orthogonal to each other, but are not limited thereto, and mayintersect with each other at an acute angle or an obtuse angle. Further,the pitch P₂ of the antenna connection wiring 22 is uniform in thelongitudinal direction of the antenna pattern region 20 (Y direction),but is not limited thereto, and may be non-uniform in the longitudinaldirection (Y direction).

As illustrated in FIGS. 41 and 42, a cross-sectional shape of each ofthe antenna wirings 21 and each of the antenna connection wirings 22 issubstantially the same as that in the case of the second embodiment.Further, the same material as that in the case of the second embodimentcan be used as each material of the antenna wiring 21 and the antennaconnection wiring 22.

Meanwhile, in the present embodiment, the widthwise central portion 20 cof the antenna pattern region 20 has a predetermined aperture ratio Ac,and each of the widthwise edge portions 20 e ₁ and 20 e ₂ of the antennapattern region 20 has a predetermined aperture ratio Ae. Among these,the aperture ratio Ac in the widthwise central portion 20 c can be set,for example, in a range of 87% or more and less than 100%. Further, theaperture ratio Ae in the widthwise edge portions 20 e ₁ and 20 e ₂ canbe set, for example, in a range of 85% or more and 99% or less. Asdescribed above, the plurality of antenna wirings 21 are arranged at therelatively wide pitch P_(1A) in the widthwise central portion 20 c ofthe antenna pattern region 20, and arranged at the relatively narrowpitch P_(1B) in the widthwise edge portions 20 e ₁ and 20 e ₂. Thus, theaperture ratio Ac in the widthwise central portion 20 c of the antennapattern region 20 is higher than the aperture ratio Ae in the widthwiseedge portions 20 e ₁ and 20 e ₂ of the antenna pattern region 20(Ac>Ae). As a result, a current distribution in the antenna patternregion 20 can be made more uniform as will be described later, andantenna characteristics can be improved.

Further, a difference between the aperture ratio Ac in the widthwisecentral portion 20 c of the antenna pattern region 20 and the apertureratio Ae in the widthwise edge portions 20 e ₁ and 20 e ₂ of the antennapattern region 20 (|Ac−Ae|) is preferably set in a range of more than 0%and 15% or less. As the difference between the aperture ratio Ac and theaperture ratio Ae is set in the above range in this manner, it ispossible to make the current distribution in the antenna pattern region20 more uniform while maintaining the function as the antenna in theantenna pattern region 20.

Furthermore, a total aperture ratio At of the antenna pattern region 20can be set, for example, in a range of 87% or more and less than 100%.As the total aperture ratio At of the wiring board 10 is set in thisrange, the conductivity and transparency of the wiring board 10 can beensured.

Note that the aperture ratio refers to a ratio (%) of an area of anopening region (region where the metal portions such as the antennawiring 21 and the antenna connection wiring 22 are not present and thesubstrate 11 is exposed) accounting for a unit area of a predeterminedregion (for example, a part of the antenna pattern region 20).

Further, a configuration of the power feeding unit 40 is substantiallythe same as that in the case of the second embodiment.

[Method for Manufacturing Wiring Board]

Next, a method for manufacturing the wiring board according to thepresent embodiment will be described with reference to FIGS. 43(a) to43(h). FIGS. 43(a) to 43(h) are cross-sectional views illustrating themethod for manufacturing the wiring board according to the presentembodiment.

First, the substrate 11 is prepared, and the conductive layer 51 isformed on substantially the entire front surface of the substrate 11 asillustrated in FIG. 43(a). In the present embodiment, a thickness of theconductive layer 51 is 200 nm.

However, the thickness of the conductive layer 51 can be appropriatelyselected in a range of 10 nm or more and 1000 nm or less without beinglimited thereto. In the present embodiment, the conductive layer 51 isformed by a sputtering method using copper. As a method for forming theconductive layer 51, a plasma CVD method may be used.

Next, the photocurable insulating resist 52 is supplied to substantiallythe entire front surface of the substrate 11 as illustrated in FIG.43(b). Examples of the photocurable insulating resist 52 include anorganic resin such as an epoxy resin.

Subsequently, the transparent mold 53 for imprinting having theprotrusion 53 a is prepared (FIG. 43(c)), and the mold 53 and thesubstrate 11 are brought close to each other, and the photocurableinsulating resist 52 is developed between the mold 53 and the substrate11. Next, light irradiation is performed from the mold 53 side to curethe photocurable insulating resist 52, thereby forming an insulatinglayer 54. As a result, a trench 54 a having a shape in which theprotrusion 53 a has been transferred is formed on a front surface of theinsulating layer 54. The trench 54 a has a planar shape patterncorresponding to the antenna wiring 21 and the antenna connection wiring22.

Thereafter, the mold 53 is separated from the insulating layer 54 toobtain the insulating layer 54 having a cross-sectional structureillustrated in FIG. 43(d). A direction in which the mold 53 is separatedfrom the insulating layer 54 is preferably the Y direction in which thelonger antenna wiring 21 extends.

As the trench 54 a is formed on the front surface of the insulatinglayer 54 by the imprinting method in this manner, a fine shape of thetrench 54 a can be made. Note that the insulating layer 54 may be formedby a photolithography method without being limited thereto. In thiscase, a resist pattern is formed by the photolithography method so as toexpose the conductive layer 51 corresponding to the antenna wiring 21and the antenna connection wiring 22.

As illustrated in FIG. 43(d), a residue of an insulating material mayremain at a bottom of the trench 54 a of the insulating layer 54. Thus,the residue of the insulating material is removed by performing a wettreatment using a permanganate solution or N-methyl-2-pyrrolidone or adry treatment using oxygen plasma. As the residue of the insulatingmaterial is removed in this manner, the trench 54 a exposing theconductive layer 51 can be formed as illustrated in FIG. 43(e).

Next, the trench 54 a of the insulating layer 54 is filled with theconductor 55 as illustrated in FIG. 43(f). In the present embodiment,the trench 54 a of the insulating layer 54 is filled with copper by anelectrolytic plating method using the conductive layer 51 as a seedlayer.

Subsequently, the insulating layer 54 is removed as illustrated in FIG.43(g). In this case, the wet treatment using a permanganate solution orN-methyl-2-pyrrolidone or the dry treatment using oxygen plasma isperformed to remove the insulating layer 54 on the substrate 11.

Thereafter, the conductive layer 51 on the front surface of thesubstrate 11 is removed as illustrated in FIG. 43(h). At this time, theconductive layer 51 is etched so as to expose the front surface of thesubstrate 11 by performing a wet process using a hydrogen peroxidesolution. In this manner, the wiring board 10, which includes thesubstrate 11 and the antenna pattern region 20 arranged on the substrate11, is obtained. In this case, the antenna pattern region 20 includesthe antenna wiring 21 and the antenna connection wiring 22. Theabove-described conductor 55 includes the antenna wiring 21 and theantenna connection wiring 22. At this time, the power feeding unit 40may be formed by a part of the conductor 55.

Alternatively, the power feeding unit 40 having a flat plate shape maybe separately prepared, and this power feeding unit 40 may beelectrically connected to the antenna pattern region 20.

[Operation of Present Embodiment]

Next, an operation of the wiring board having such a configuration willbe described.

As illustrated in FIG. 44, the wiring board 10 is incorporated in theimage display device 90 including the display 91. The wiring board 10 isarranged on the display 91. Examples of such an image display device 90include a mobile terminal device such as a smartphone and a tablet. Theantenna pattern region 20 of the wiring board 10 is electricallyconnected to the wireless communication circuit 92 of the image displaydevice 90 via the power feeding unit 40. In this manner, radio waves ofa predetermined frequency can be transmitted and received via theantenna pattern region 20 so that communication can be performed usingthe image display device 90.

Meanwhile, in general, a current value flowing through the antennapattern region 20 is not uniform in the width direction (X direction)during transmission and reception of a radio wave using the antennapattern region 20. Specifically, a current value flowing through thewidthwise edge portions 20 e ₁ and 20 e ₂ of the antenna pattern region20 is larger than a current value flowing through the widthwise centralportion 20 c of the antenna pattern region 20.

FIG. 51 illustrates, as a reference example, a value of a flowingcurrent calculated with a uniform mesh-like antenna pattern and auniform plate-like antenna pattern. In FIG. 51, the horizontal axisrepresents a position in the width direction of the antenna pattern, theleft end of the horizontal axis indicates the widthwise edge portion ofthe antenna pattern, and the right end of the horizontal axis indicatesthe widthwise central portion of the antenna pattern. Further, thevertical axis represents a value of a current flowing through theantenna pattern. As apparent from FIG. 51, when the antenna pattern isthe uniform mesh shape and the uniform plate shape, the current value islarger in the widthwise edge portion of the antenna pattern than in thewidthwise central portion of the antenna pattern in both the cases. Inthis case, it is difficult to sufficiently improve antennacharacteristics since the current distribution in the antenna pattern isnot uniform.

In the present embodiment, however, the aperture ratio Ac in thewidthwise central portion 20 c of the antenna pattern region 20 is setto be higher than the aperture ratio Ae in the widthwise edge portions20 e ₁ and 20 e ₂ of the antenna pattern region 20 (Ac>Ae). That is, thedensity (the pitch P_(1A)) of the antenna wirings 21 in the widthwiseedge portions 20 e ₁ and 20 e ₂ having the high current value is set tobe higher than the density (the pitch P_(1B)) of the antenna wirings 21in the widthwise central portion 20 c having the lower current value. Asa result, as compared to the case where the mesh of the antenna patternis uniform, the current distribution is made uniform between thewidthwise central portion 20 c and the widthwise edge portions 20 e ₁and 20 e ₂ of the antenna pattern region 20 so that the antennacharacteristics can be further improved.

Further, according to the present embodiment, the wiring board 10includes: the substrate 11 having transparency and the antenna patternregion 20 including the plurality of antenna wirings 21 each of which isarranged on the substrate 11 and has the function as the antenna, andthus, the transparency of the wiring board 10 is ensured. As a result,when the wiring board 10 is arranged on the display 91, the display 91can be seen through the opening portion 23 of the antenna pattern region20, so that the visibility of the display 91 is not hindered.

Further, the antenna pattern region 20 includes the plurality of antennaconnection wirings 22 connecting the plurality of antenna wirings 21according to the present embodiment. As a result, it is possible to makethe disconnection of the antenna wiring 21 difficult, and to suppress adecrease in the function of the antenna wiring 21 as the antenna.

[Modifications]

Next, various modifications of the wiring board will be described withreference to FIGS. 45 to 50. FIGS. 45 to 50 are views illustrating thevarious modifications of the wiring board. The modifications illustratedin FIGS. 45 to 50 are different in terms of the configuration of theantenna pattern region 20 and/or the power feeding unit 40, and theother configurations thereof are substantially the same as those of theabove-described embodiment illustrated in FIGS. 38 to 44. In FIGS. 45 to50, the same portions as those of the modes illustrated in FIG. 38 toFIG. 44 are denoted by the same reference signs, and detaileddescriptions thereof will be omitted.

[First Modification]

FIG. 45 illustrates a wiring board 10P according to a firstmodification. In FIG. 45, a void portion 61 is formed in the widthwisecentral portion 20 c of the antenna pattern region 20. The void portion61 has a substantially rectangular shape in a plan view, and has alongitudinal direction parallel to the Y direction. In the void portion61, the antenna wiring 21 and the antenna connection wiring 22 are notprovided, and the substrate 11 is exposed. A width W_(b) (length in theX direction) of the void portion 61 may be set, for example, in a rangeof about 20% or more and 80% or less of the width W_(a) of the antennapattern region 20.

The antenna pattern region 20 has a first pattern region 20 f and asecond pattern region 20 g separated with the void portion 61therebetween. In the first pattern region 20 f and the second patternregion 20 g, metal lines are formed in a lattice shape or a mesh shape,respectively. Each of the first pattern region 20 f and the secondpattern region 20 g includes the plurality of antenna wirings 21 and theplurality of antenna connection wirings 22.

Both the widthwise edge portions 20 e ₁ and 20 e ₂ of the antennapattern region 20 are arranged in the first pattern region 20 f and thesecond pattern region 20 g, respectively. That is, the widthwise edgeportion 20 e ₁ on the negative side in the X direction is arranged inthe first pattern region 20 f, and the widthwise edge portion 20 e ₂ onthe positive side in the X direction is arranged in the second patternregion 20 g. The width W_(c) (length in the X direction) of each of thefirst pattern region 20 f and the second pattern region 20 g may be set,for example, in a range of about 10% or more and 40% or less of thewidth W_(a) of the antenna pattern region 20. Note that the width W_(c)of the first pattern region 20 f and the width W_(c) of the secondpattern region 20 g are equal to each other in FIG. 45, but may bedifferent from each other.

Further, the first pattern region 20 f and the second pattern region 20g are electrically connected to each other by a central pattern region20 h. In the central pattern region 20 h, the respective metal lines areformed in a lattice shape or a mesh shape. The central pattern region 20h includes the plurality of antenna wirings 21 and the plurality ofantenna connection wirings 22. Further, the central pattern region 20 his arranged in the widthwise central portion 20 c of the antenna patternregion 20. A width (length in the X direction) of the central patternregion 20 h is equal to the width W_(b) of the void portion 61. Further,a length L_(b) in the Y direction of the central pattern region 20 h canbe selected, for example, in the range of 0.05 mm or more and 5.0 mm orless.

In FIG. 45, the aperture ratio Ac in the widthwise central portion 20 cof the antenna pattern region 20 is higher than the aperture ratio Ae inthe widthwise edge portions 20 e ₁ and 20 e ₂. That is, a pitch of theantenna wiring 21 in the widthwise central portion 20 c of the antennapattern region 20 (the central pattern region 20 h) is wider than apitch of the antenna wiring 21 in the widthwise edge portions 20 e ₁ and20 e ₂ of the antenna pattern region 20 (the first pattern region 20 fand the second pattern region 20 g). As a result, a current distributioncan be made uniform between the widthwise central portion 20 c and thewidthwise edge portions 20 e ₁ and 20 e ₂ of the antenna pattern region20. Furthermore, the transparency of the wiring board 10 can be improvedsince the void portion 61 is formed in the widthwise central portion 20c of the antenna pattern region 20.

[Second Modification]

FIG. 46 illustrates a wiring board 10Q according to a secondmodification. The wiring board 10Q illustrated in FIG. 46 has the dummypattern region 30 formed in the void portion 61 of the wiring board 10Pillustrated in FIG. 45 (first modification). This dummy pattern region30 is provided between the first pattern region 20 f and the secondpattern region 20 g. The dummy pattern region 30 does not substantiallyfunction as an antenna, which is different from the antenna patternregion 20.

The dummy pattern region 30 is configured by repeating the dummy wiring30 a having a predetermined unit pattern shape. That is, the dummypattern region 30 includes a plurality of the dummy wirings 30 a eachhaving the same shape, and each of the dummy wirings 30 a iselectrically independent of the antenna pattern region 20 (the antennawiring 21 and the antenna connection wiring 22). Further, the pluralityof dummy wirings 30 a are regularly arranged over the entire region ofthe dummy pattern region 30. The plurality of dummy wirings 30 a arespaced apart from each other in a plane direction, and are arranged inan island shape to protrude above the substrate 11. That is, each of thedummy wirings 30 a is electrically independent of the antenna patternregion 20, the power feeding unit 40, and the other dummy wirings 30 a.Each of the dummy wirings 30 a has a substantially L shape in a planview. Note that a width of the dummy wiring 30 a (length in the Xdirection) may be gradually narrowed from the central portion in thewidth direction (X direction) of the dummy pattern region 30 toward theedge portion in the width direction (X direction) in accordance with thepitch of the antenna wiring 21.

In this case, the dummy wiring 30 a has a shape in which a part of theabove-described unit pattern shape 20 a (see FIG. 40(a)) of the antennapattern region 20 is missing. That is, the shape of the dummy wiring 30a is a shape obtained by removing a part of the L-shaped unit patternshape 20 a of the antenna pattern region 20. As a result, it is possibleto make it difficult to visually recognize a difference between theantenna pattern region 20 and the dummy pattern region 30, and to makethe antenna pattern region 20 arranged on the substrate 11 hardlyvisible.

As the dummy pattern region 30 electrically independent of the antennapattern region 20 is arranged in the void portion 61 in this manner, aboundary between the antenna pattern region 20 and the void portion 61can be made obscure. As a result, it is possible to make the antennapattern region 20 hardly visible on the front surface of the display 91,and to make it difficult for a user of the image display device 90 torecognize the antenna pattern region 20 with the naked eye.

[Third Modification]

FIG. 47 illustrates a wiring board 10R according to a thirdmodification. In FIG. 47, a length (length in the Y direction) L_(c) ofthe power feeding unit 40 in a widthwise central portion 40 c is set tobe longer than a length (length in the Y direction) L_(d) of the powerfeeding unit 40 in each of widthwise edge portions 40 e ₁ and 40 e ₂.That is, the power feeding unit 40 has a triangular shape in a planview, and the length of the power feeding unit 40 (the length in the Ydirection) is gradually shorten from the widthwise central portion 40 ctoward the widthwise edge portions 40 e ₁ and 40 e ₂. The power feedingunit 40 has a straight long side 41 a electrically connected to theantenna pattern region 20, and a pair of straight short sides 41 b and41 c each of which is connected to the long side 41 a. Note that theplanar shape of the power feeding unit 40 is not limited to thetriangular shape. For example, the short sides 41 b and 41 c may beformed in a step shape or an arc shape such as a circular arc.

As the length L_(c) of the power feeding unit 40 in the widthwisecentral portion 40 c is made longer than the length L_(d) in each of thewidthwise edge portions 40 e ₁ and 40 e ₂ in this manner, a current islikely to concentrate on the widthwise central portion 40 c of the powerfeeding unit 40. As a result, a current distribution is made moreuniform between the widthwise central portion 20 c and the widthwiseedge portions 20 e ₁ and 20 e ₂ of the antenna pattern region 20 so thatthe antenna characteristics can be further improved. Further, it ispossible to disperse heat generated in the power feeding unit 40 and tosuppress a temperature rise of the power feeding unit 40 by increasingthe length L_(c) of the widthwise central portion 40 c of the powerfeeding unit 40 where the current is likely to concentrate. Furthermore,the entire area of the power feeding unit 40 can be reduced, and thus,the weight of the wiring board 10 can be reduced.

[Fourth Modification]

FIG. 48 illustrates a wiring board 10S according to a fourthmodification. In FIG. 48, the void portion 61 in which the antennawiring 21 and the antenna connection wiring 22 are not provided isformed in the widthwise central portion 20 c of the antenna patternregion 20. Further, the antenna pattern region 20 has the first patternregion 20 f and the second pattern region 20 g separated with the voidportion 61 therebetween. A configuration of this antenna pattern region20 is substantially the same as the configuration of the antenna patternregion 20 of the wiring board 10P illustrated in FIG. 45 (firstmodification).

Further, the power feeding unit 40 has a triangular shape, and a length(length in the Y direction) of the power feeding unit 40 in thewidthwise central portion 40 c is set to be longer than a length (lengthin the Y direction) of the power feeding unit 40 in each of thewidthwise edge portions 40 e ₁ and 40 e ₂. A configuration of this powerfeeding unit 40 is substantially the same as the configuration of thepower feeding unit 40 of the wiring board 10R illustrated in FIG. 47(third modification).

In this case, the transparency of the wiring board 10 can be improved,and a current distribution in the antenna pattern region 20 can be mademore uniform.

[Fifth Modification]

FIG. 49 illustrates a wiring board 10T according to a fifthmodification. In FIG. 49, connection pattern regions 20 m and 20 n areprovided, respectively, between the central pattern region 20 h of theantenna pattern region 20 and each of the first pattern region 20 f andthe second pattern region 20 g. One connection pattern region 20 m isprovided between the central pattern region 20 h and the first patternregion 20 f, and the other connection pattern region 20 n is providedbetween the central pattern region 20 h and the second pattern region 20g.

The connection pattern regions 20 m and 20 n have a substantiallytriangular shape in a plan view, and have inclined portions 20 p and 20q formed obliquely with respect to the width direction (X direction) ofthe antenna pattern region 20, respectively. Each of the inclinedportions 20 p and 20 q extends linearly, but is not limited thereto, andmay extend in a curved shape or a step shape. Further, the connectionpattern regions 20 m and 20 n may include the antenna wiring 21 and theantenna connection wiring 22 formed in a lattice shape or a mesh shapesimilarly to the central pattern region 20 h and the second patternregion 20 g. The other configurations are substantially the same as theconfigurations of the wiring board 10S illustrated in FIG. 48 (fourthmodification).

In this case, the transparency of the wiring board 10 can be improved,and a current distribution in the antenna pattern region 20 can be mademore uniform.

[Sixth Modification]

FIG. 50 illustrates a wiring board 10U according to a sixthmodification. In FIG. 50, each of the antenna pattern regions 20includes the plurality of antenna wirings 21 each having a function asan antenna and the plurality of antenna connection wirings 22 thatconnect the plurality of antenna wirings 21. In this case, the pluralityof antenna wirings 21 are arranged at equal intervals. Further, theplurality of antenna connection wirings 22 are arranged at equalintervals. Note that a configuration of this power feeding unit 40 issubstantially the same as the configuration of the power feeding unit 40of the wiring board 10R illustrated in FIG. 47 (third modification).

Since the plurality of antenna wirings 21 and the plurality of antennaconnection wirings 22 are arranged at equal intervals in this manner,there is no variation in size of the opening portion 23 in each of theantenna pattern regions 20, and it is possible to make the antennapattern region 20 less visible with the naked eye. Further, a currentdistribution in the antenna pattern region 20 can be made more uniform.

The plurality of components disclosed in the above-described embodimentsand modifications can be appropriately combined if necessary.Alternatively, some components may be deleted from all the componentsillustrated in the above-described embodiments and modifications.

1. A wiring board comprising: a substrate having transparency; aplurality of first wiring which are arranged on an upper surface of thesubstrate and extend in a first direction and each of which has a backsurface in contact with the substrate and a front surface facing anopposite side of the back surface; and a second wiring which is arrangedon the upper surface of the substrate, extends in a second directionintersecting with the first direction, and has a back surface in contactwith the substrate and a front surface facing an opposite side of theback surface, wherein the first wiring has a pair of side surfaces whichextend in the first direction and are adjacent to the back surface ofthe first wiring, and each of the pair of side surfaces of the firstwiring is recessed inward, and the second wiring has a pair of sidesurfaces which extend in the second direction and are adjacent to theback surface of the second wiring, and each of the pair of side surfacesof the second wiring is recessed inward.
 2. A wiring board comprising: asubstrate having transparency; a plurality of first wiring which arearranged on an upper surface of the substrate and extend in a firstdirection and each of which has a back surface in contact with thesubstrate and a front surface facing an opposite side of the backsurface; and a second wiring which is arranged on the upper surface ofthe substrate, extends in a second direction intersecting with the firstdirection, and has a back surface in contact with the substrate and afront surface facing an opposite side of the back surface, wherein thefirst wiring has a pair of side surfaces which extend in the firstdirection and are adjacent to the back surface of the first wiring, thesecond wiring has a pair of side surfaces which extend in the seconddirection and are adjacent to the back surface of the second wiring, andone side surface of the first wiring and one side surface of the secondwiring are continuously connected by a curved surface.
 3. A wiring boardcomprising: a substrate having transparency; a plurality of firstwirings which are arranged on an upper surface of the substrate andextend in a first direction and each of which has a back surface incontact with the substrate and a front surface facing an opposite sideof the back surface; and a second wiring which is arranged on the uppersurface of the substrate, extends in a second direction intersectingwith the first direction, and has a back surface in contact with thesubstrate and a front surface facing an opposite side of the backsurface, wherein a line width of the back surface of the second wiringis smaller than a line width of the back surface of the first wiring. 4.The wiring board according to claim 3, wherein the line width of theback surface of the first wiring is larger than a line width of thefront surface of the first wiring, and the line width of the backsurface of the second wiring is larger than a line width of the frontsurface of the second wiring.
 5. The wiring board according to claim 3,wherein the second wiring has a pair of side surfaces which extend inthe second direction and are adjacent to the back surface of the secondwiring, and an angle between the front surface and each of the sidesurfaces of the second wiring is smaller than an external angle of anangle between the back surface and each of the side surfaces of thesecond wiring.
 6. The wiring board according to claim 3, wherein thefirst wiring has a pair of side surfaces which extend in the firstdirection and are adjacent to the back surface of the first wiring, andan angle between the front surface and each of the side surfaces of thefirst wiring is smaller than an external angle of an angle between theback surface and each of the side surfaces of the first wiring.
 7. Thewiring board according to claim 3, wherein an intersection between thefirst wiring and the second wiring includes a curved surface at at leastone of corners formed by the upper surface of the substrate, a surfaceadjacent to the back surface of the first wiring, and a surface adjacentto the back surface of the second wiring, the curved surface beingcontinuous among the surfaces.
 8. The wiring board according to claim 1,having a radio wave transmission/reception function.
 9. A method formanufacturing a wiring board, comprising: forming a conductive layer onan upper surface of a substrate; forming an insulating layer thatincludes a first trench extending in a first direction and a secondtrench extending in a second direction; forming a first conductorarranged in the first trench and a second conductor arranged in thesecond trench; removing the insulating layer; and removing theconductive layer to expose the upper surface of the substrate andforming a first wiring and a second wiring from the first conductor andthe second conductor.
 10. The method for manufacturing a wiring boardaccording to claim 9, wherein the first wiring has a pair of sidesurfaces which extend in the first direction and are adjacent to a backsurface of the first wiring, and each of the pair of side surfaces ofthe first wiring is recessed inward, and the second wiring has a pair ofside surfaces which extend in the second direction and are adjacent to aback surface of the second wiring, and each of the pair of side surfacesof the second wiring is recessed inward.
 11. The method formanufacturing a wiring board according to claim 9, wherein the firstwiring has a pair of side surfaces which extend in the first directionand are adjacent to a back surface of the first wiring, the secondwiring has a pair of side surfaces which extend in the second directionand are adjacent to a back surface of the second wiring, and one sidesurface of the first wiring and one side surface of the second wiringare continuously connected by a curved surface.
 12. The method formanufacturing a wiring board according to claim 9, wherein a line widthof a back surface of the second wiring is smaller than a line width of aback surface of the first wiring.
 13. The method for manufacturing awiring board according to claim 9, wherein the insulating layer thatincludes the first trench and the second trench is formed using animprinting method.
 14. The method for manufacturing a wiring boardaccording to claim 9, wherein a method for forming the first wiring andthe second wiring comprises: forming the conductive layer by asputtering method; forming the first wiring and the second wiring by anelectrolytic plating method; and removing the conductive layer by wetetching so as to expose the upper surface of the substrate.
 15. Themethod for manufacturing a wiring board according to claim 9, furthercomprising performing a blackening treatment on front surfaces of thefirst wiring and the second wiring.
 16. A wiring board comprising: asubstrate having transparency; a wiring pattern region which is arrangedon the substrate and includes a plurality of wirings; and a dummypattern region which is arranged around the wiring pattern region andincludes a plurality of dummy wirings electrically independent of thewirings, wherein each of the wiring pattern region and the dummy patternregion is formed by repeating a predetermined unit pattern shape, and aunit pattern shape of the dummy pattern region is a shape in which apart of a unit pattern shape of the wiring pattern region is missing,and an additional pattern apart from the dummy wiring is arranged in thedummy pattern region.
 17. The wiring board according to claim 16,wherein the dummy wiring has a first dummy wiring portion and a seconddummy wiring portion, and the first dummy wiring portion and the seconddummy wiring portion are arranged apart from each other in a planedirection.
 18. A wiring board comprising: a substrate havingtransparency; a wiring pattern region which is arranged on the substrateand includes a plurality of wirings; and a dummy pattern region which isarranged around the wiring pattern region and includes a plurality ofdummy wirings electrically independent of the wirings, wherein the dummywiring has a substantially L shape in a plan view.
 19. The wiring boardaccording to claim 18, wherein an additional pattern apart from thedummy wiring is arranged in the dummy pattern region.
 20. A wiring boardcomprising: a substrate having transparency; a wiring pattern regionwhich is arranged on the substrate and includes a plurality of wirings;and a dummy pattern region which is arranged around the wiring patternregion and includes a plurality of dummy wirings electricallyindependent of the wirings, wherein the dummy wiring has a first dummywiring portion and a second dummy wiring portion, and the first dummywiring portion and the second dummy wiring portion are arrangedobliquely with respect to the wiring.
 21. The wiring board according toclaim 16, wherein an aperture ratio of the dummy pattern region ishigher than an aperture ratio of the wiring pattern region.
 22. Thewiring board according to claim 21, wherein the aperture ratio of thedummy pattern region is in a range of 87% or more and less than 100%.23. The wiring board according to claim 16, wherein a difference betweenthe aperture ratio of the dummy pattern region and the aperture ratio ofthe wiring pattern region is 1% or less.
 24. The wiring board accordingto claim 16, wherein the wiring pattern region includes a plurality ofconnection wirings that connect the plurality of wirings.
 25. The wiringboard according to claim 16 having a radio wave transmission/receptionfunction.
 26. A wiring board comprising: a substrate havingtransparency; and an antenna pattern region which is arranged on thesubstrate and includes a plurality of antenna wirings having a functionas an antenna, wherein an aperture ratio of a widthwise central portionof the antenna pattern region is higher than an aperture ratio of awidthwise edge portion of the antenna pattern region.
 27. The wiringboard according to claim 26, wherein a pitch of the plurality of antennawirings in the widthwise central portion of the antenna pattern regionis wider than a pitch of the plurality of antenna wirings in a widthwiseedge portion of the antenna pattern region.
 28. The wiring boardaccording to claim 26, wherein a void portion in which the antennawiring is not provided is formed in the widthwise central portion of theantenna pattern region.
 29. The wiring board according to claim 28,wherein a dummy pattern region including a plurality of dummy wiringselectrically independent of the antenna wiring is formed in the voidportion.
 30. The wiring board according to claim 28, wherein the antennapattern region has a first pattern region and a second pattern regionseparated with the void portion therebetween, the first pattern regionand the second pattern region are respectively arranged on bothwidthwise edge portions of the antenna pattern region, and the firstpattern region and the second pattern region are electrically connectedto each other by a central pattern region.
 31. The wiring boardaccording to claim 30, wherein connection pattern regions each having aninclined portion formed obliquely to a width direction of the antennapattern region are provided between the central pattern region and eachof the first pattern region and the second pattern region.
 32. Thewiring board according to claim 26, wherein a power feeding unit iselectrically connected to the antenna pattern region, and a length ofthe power feeding unit in the widthwise central portion is longer than alength of the power feeding unit in the widthwise edge portion.
 33. Awiring board comprising: a substrate having transparency; an antennapattern region which is arranged on the substrate and includes aplurality of antenna wirings having a function as an antenna; and apower feeding unit electrically connected to the antenna pattern region,wherein a length of the power feeding unit in a widthwise centralportion is longer than a length of the power feeding unit in a widthwiseedge portion.
 34. A method for manufacturing a wiring board, comprising:a step of preparing a substrate having transparency; and a step offorming an antenna pattern region, which includes a plurality of antennawirings each having a function as an antenna, on the substrate, whereinan aperture ratio of a widthwise central portion of the antenna patternregion is higher than an aperture ratio of a widthwise edge portion ofthe antenna pattern region.
 35. A method for manufacturing a wiringboard, comprising: a step of preparing a substrate having transparency;and a step of forming an antenna pattern region including a plurality ofantenna wirings each having a function as an antenna and a power feedingunit electrically connected to the antenna pattern region on thesubstrate, wherein a length of the power feeding unit in a widthwisecentral portion is longer than a length of the power feeding unit in awidthwise edge portion.